Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Mar. 31, 2018	May 29, 2018	Sep. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Trading Symbol	ONVO
Entity Registrant Name	ORGANOVO HOLDINGS, INC.
Entity Central Index Key	0001497253
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		111,126,625
Entity Public Float			$ 232,023,855

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Current Assets
Cash and cash equivalents	$ 43,726	$ 62,751
Accounts receivable	883	647
Grant receivable	145	0
Inventory, net	842	550
Prepaid expenses and other current assets	1,164	1,144
Total current assets	46,760	65,092
Fixed assets, net	2,788	3,840
Restricted cash	127	127
Other assets, net	152	121
Total assets	49,827	69,180
Current Liabilities
Accounts payable	464	1,171
Accrued expenses	3,341	4,101
Deferred revenue	668	582
Deferred rent	185	157
Total current liabilities	4,658	6,011
Deferred revenue, net of current portion	19	58
Deferred rent, net of current portion	564	749
Total liabilities	5,241	6,818
Commitments and Contingencies	0	0
Stockholders' Equity
Common stock, $0.001 par value; 150,000,000 shares authorized, 111,032,957 and 104,551,466 shares issued and outstanding at March 31, 2018 and March 31, 2017, respectively	111	104
Additional paid-in capital	278,595	261,586
Accumulated deficit	(234,120)	(199,317)
Accumulated other comprehensive income (loss)	0	(11)
Total stockholders' equity	44,586	62,362
Total Liabilities and Stockholders' Equity	$ 49,827	$ 69,180

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Mar. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	111,032,957	104,551,466
Common stock, shares outstanding	111,032,957	104,551,466

Consolidated Statements of Operations and Other Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Revenues
Products and services	$ 3,627	$ 3,167	$ 806
Collaborations and licenses	422	1,022	486
Grants	554	41	191
Total Revenues	4,603	4,230	1,483
Cost of revenues	1,030	956	0
Research and development expenses	17,956	19,545	18,008
Selling, general, and administrative expense	20,888	22,304	22,118
Total costs and expenses	39,874	42,805	40,126
Loss from Operations	(35,271)	(38,575)	(38,643)
Other Income (Expense)
Change in fair value of warrant liabilities	0	4	(17)
Gain (loss) on fixed asset disposals	4	(51)	0
Interest income	478	198	88
Other income (expense)	(12)	0	0
Total Other Income (Expense)	470	151	71
Income Tax Expense	(2)	(23)	(3)
Net Loss	$ (34,803)	$ (38,447)	$ (38,575)
Net loss per common share—basic and diluted	$ (0.32)	$ (0.39)	$ (0.43)
Weighted average shares used in computing net loss per common share—basic and diluted	107,243,974	97,763,032	90,057,356
Comprehensive Loss:
Net Loss	$ (34,803)	$ (38,447)	$ (38,575)
Currency Translation Adjustment	11	(11)	0
Comprehensive Loss	$ (34,792)	$ (38,458)	$ (38,575)

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Mar. 31, 2015	$ 48,696	$ 82	$ 170,909	$ (122,295)	$ 0
Beginning balance, Shares at Mar. 31, 2015		81,537,000
Issuance of common stock from warrant exercises, net	$ 0	$ 0	0	0	0
Issuance of common stock from warrant exercises, net, Shares	32,914	32,000
Restricted stock forfeitures	$ 0	$ 0	0	0	0
Restricted stock forfeitures, Shares		(132,000)
Issuance of common stock from public offering, net	43,137	$ 10	43,127	0	0
Issuance of common stock from public offering, Shares		10,839,000
Stock-based compensation expense	8,556	$ 0	8,556	0	0
Warrant liability removed due to exercises of warrants	139	0	139	0	0
Stock option exercises	$ 320	$ 0	320	0	0
Stock option exercises, Shares	116,001	116,000
Issuance of warrants to consultant	$ 38	$ 0	38	0	0
Expense related to potential equity bonus issuance	(130)	0	(130)	0	0
Net loss	(38,575)	0	0	(38,575)	0
Currency Translation Adjustment	0
Ending balance at Mar. 31, 2016	62,181	$ 92	222,959	(160,870)	0
Ending balance, Shares at Mar. 31, 2016		92,392,000
Issuance of common stock from warrant exercises, net	$ 336	$ 1	335	0	0
Issuance of common stock from warrant exercises, net, Shares	700,379	700,000
Issuance of common stock under employee and director stock option, RSU and purchase plans	$ 705	$ 0	705	0	0
Issuance of common stock under employee and director stock option, RSU and purchase plans, Shares		397,000
Issuance of common stock from public offering, net	30,206	$ 11	30,195	0	0
Issuance of common stock from public offering, Shares		11,062,000
Stock-based compensation expense	$ 7,392	$ 0	7,392	0	0
Stock option exercises, Shares	245,271
Net loss	$ (38,447)	0	0	(38,447)	0
Currency Translation Adjustment	(11)	0	0	0	(11)
Ending balance at Mar. 31, 2017	$ 62,362	$ 104	261,586	(199,317)	(11)
Ending balance, Shares at Mar. 31, 2017		104,551,000
Issuance of common stock from warrant exercises, net, Shares	0
Issuance of common stock under employee and director stock option, RSU and purchase plans	$ 114	$ 1	113	0	0
Issuance of common stock under employee and director stock option, RSU and purchase plans, Shares		675,000
Issuance of common stock from public offering, net	9,173	$ 5	9,168	0	0
Issuance of common stock from public offering, Shares		5,307,000
Stock-based compensation expense	6,903	$ 0	6,903	0	0
Stock option exercises	$ 826	$ 1	825	0	0
Stock option exercises, Shares	500,000	500,000
Net loss	$ (34,803)	$ 0	0	(34,803)	0
Currency Translation Adjustment	11	0	0	0	11
Ending balance at Mar. 31, 2018	$ 44,586	$ 111	$ 278,595	$ (234,120)	$ 0
Ending balance, Shares at Mar. 31, 2018		111,033,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Cash Flows From Operating Activities
Net loss	$ (34,803)	$ (38,447)	$ (38,575)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of deferred financing costs	0	0	(92)
(Gain) loss on disposal of fixed assets	(4)	56	0
Depreciation and amortization	1,267	1,149	815
Change in fair value of warrant liabilities	0	(4)	17
Stock-based compensation	6,903	7,392	8,556
Donation of fixed assets	25	0	0
Increase (decrease) in cash resulting from changes in:
Accounts receivable	(236)	(388)	(259)
Grants receivable	(145)	0	0
Inventory	(292)	(216)	(268)
Prepaid expenses and other assets	5	(154)	83
Accounts payable	(707)	384	(600)
Accrued expenses	(760)	1,651	193
Deferred rent	(157)	(138)	(89)
Deferred revenue	47	(470)	851
Net cash used in operating activities	(28,857)	(29,185)	(29,368)
Cash Flows From Investing Activities
Deposits released from restriction (restricted cash deposits)	0	(48)	0
Purchases of fixed assets	(226)	(1,354)	(2,114)
Proceeds from disposals of fixed assets	4	11	14
Purchases of intangible assets	(70)	0	(35)
Net cash used in investing activities	(292)	(1,391)	(2,135)
Cash Flows From Financing Activities
Proceeds from issuance of common stock and exercise of warrants, net	9,287	30,665	43,137
Proceeds from exercise of stock options	826	582	320
Principal payments on capital lease obligations	0	0	(5)
Net cash provided by financing activities	10,113	31,247	43,452
Effect of currency exchange rate changes on cash and cash equivalents	11	(11)	0
Net Increase in Cash and Cash Equivalents	(19,025)	660	11,949
Cash and Cash Equivalents at Beginning of Period	62,751	62,091	50,142
Cash and Cash Equivalents at End of Period	43,726	62,751	62,091
Supplemental Disclosure of Cash Flow Information:
Interest	0	0	0
Income Taxes	$ 2	$ 23	$ 3

Description of Business and Summary of Significant Accounting Policies

12 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Description of Business and Summary of Significant Accounting Policies

1. Description of Business and Summary of Significant Accounting Policies

A summary of significant accounting policies, consistently applied in the preparation of the accompanying consolidated financial statements follows:

Nature of operations and basis of presentation

References in these notes to the consolidated financial statements to “Organovo Holdings, Inc.,” “Organovo Holdings,” “we,” “us,” “our,” “the Company” and “our Company” refer to Organovo Holdings, Inc. and its consolidated subsidiaries. Our consolidated financial statements include the accounts of the Company as well as its wholly-owned subsidiaries, with all material intercompany accounts and transactions eliminated in consolidation. In December 2014, we established a wholly-owned subsidiary, Samsara Sciences, Inc., to focus on the acquisition of qualified cells in support of our commercial and research endeavors. In September 2015, we established another wholly-owned subsidiary in the United Kingdom, Organovo U.K., Ltd., for the primary purpose of establishing a sales presence in Europe. At March 31, 2018, the U.K. operations have been combined with Organovo, Inc.’s operations.

Since its inception, the Company has devoted its efforts primarily to developing and commercializing a proprietary platform technology to produce and study living tissues that emulate key aspects of human biology and disease, raising capital and building infrastructure. We provide client access to our proprietary ExVive™ tissue platform to facilitate drug discovery and development through a range of research services, collaborative agreements, licenses, and grants. We also are applying our therapeutic tissue expertise to progress multiple Investigational New Drug (“IND”) Application track therapeutic programs, focusing on critical unmet medical needs in the liver disease space, including our lead program for NovoTissues® targeting Alpha-1 antitrypsin deficiency, for which we have received orphan drug designation (“ODD”) from the Food and Drug Administration (“FDA”).

The Company’s activities are subject to significant risks and uncertainties including failing to successfully develop products and services based on its technology, failing to achieve regulatory approvals for its therapeutic candidates, and failing to achieve the market acceptance necessary to generate sufficient revenues to achieve and sustain profitability.

NASDAQ listing

On August 8, 2016, the Company moved its stock exchange listing to the NASDAQ Global Market, under the “ONVO” ticker symbol. From July 11, 2013 through August 5, 2016, the Company listed its shares on the NYSE MKT. Prior to July 11, 2013, the Company’s shares were quoted on the OTC QX.

Liquidity

As of March 31, 2018, the Company had cash and cash equivalents of approximately $43.7 million and an accumulated deficit of approximately $234.1 million. The Company also had negative cash flows from operations of approximately $28.9 million during the year ended March 31, 2018.

Through March 31, 2018, the Company has financed its operations primarily through the sale of convertible notes, the private placement of equity securities, the sale of common stock through public and at-the-market (“ATM”) offerings, and through revenue derived from product and research service-based agreements, collaborative agreements, grants, and licenses. During the year ended March 31, 2018, the Company issued 5,307,105 shares of its common stock through its ATM facility and received net proceeds of approximately $9.2 million.

Based on its current operating plan and available cash resources, the Company believes it has sufficient resources to fund its business for at least the next twelve months.

The Company will need additional capital to further fund the development of its proprietary platform to produce and study living tissues that emulate key aspects of human biology and disease that can be used to facilitate drug discovery and development, as well as its therapeutic tissues focusing on critical unmet medical needs in the liver disease space. The Company intends to cover its future operating expenses through cash on hand, through revenue derived from research service agreements, product sales, collaborative agreements, grants and license payments, and through the issuance of additional equity or debt securities. Depending on market conditions, we cannot be sure that additional financing will be available when needed or that, if available, financing will be obtained on terms favorable to us or to our stockholders.

Having insufficient funds may require us to delay, scale back, or eliminate some or all of our development programs or relinquish rights to our technology on less favorable terms than we would otherwise choose. Failure to obtain adequate financing could eventually adversely affect our ability to operate as a going concern. If we raise additional funds from the issuance of equity securities, substantial dilution to our existing stockholders would likely result. If we raise additional funds by incurring debt financing, the terms of the debt may involve significant cash payment obligations as well as covenants and specific financial ratios that may restrict our ability to operate our business.

Use of estimates

The preparation of the financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect certain reported amounts and disclosures. Accordingly, actual results could differ from those estimates. Significant estimates used in preparing the consolidated financial statements include those assumed in revenue recognized under the proportional performance model, the valuation of stock-based compensation expense, and the valuation allowance on deferred tax assets.

Financial instruments

For certain of the Company’s financial instruments, including cash and cash equivalents, inventory, prepaid expenses and other assets, accounts payable, accrued expenses, deferred revenue, and capital lease obligations, the carrying amounts are generally considered to be representative of their respective fair values because of the short-term nature of those instruments.

Cash and cash equivalents

The Company considers all highly liquid investments with original maturities of 90 days or less to be cash equivalents.

Derivative financial instruments

The Company does not use derivative instruments to hedge exposures to cash flow, market or foreign currency. At March 31, 2018 and at March 31, 2017, the Company did not have any derivative liabilities measured on a fair value basis.

Historically, the Company reviewed the terms of convertible debt and equity instruments it issued to determine if they were derivative instruments, including an embedded conversion option that is required to be bifurcated and accounted for separately as a derivative financial instrument. In circumstances where a host instrument contains more than one embedded derivative instrument, including a conversion option, that is required to be bifurcated, the bifurcated derivative instruments were accounted for as a single, compound derivative instrument. Also, in connection with the sale of convertible debt and equity instruments, the Company may have issued freestanding warrants that may, depending on their terms, have been accounted for as derivative instrument liabilities, rather than as equity.

Derivative instruments were initially recorded at fair value and were revalued at each reporting date with changes in the fair value reported as non-operating income or expense. When the convertible debt or equity instruments contain embedded derivative instruments that were to be bifurcated and accounted for as liabilities, the total proceeds allocated to the convertible host instruments were first allocated to the fair value of all the bifurcated derivative instruments. The remaining proceeds, if any, were then allocated to the convertible instruments themselves, usually resulting in those instruments being recorded at a discount from their face value.

Foreign Currency

The functional currency of our wholly owned subsidiary in the United Kingdom is the pound sterling. Accordingly, all assets and liabilities of this subsidiary are translated to US dollars based on the applicable exchange rate on the balance sheet date. Revenue and expense components are translated to US dollars at the exchange rates in effect during the period. Gains and losses resulting from foreign currency translation are reported as a separate component of accumulated other comprehensive income or loss in the equity section of our consolidated balance sheets.

Foreign currency transaction gains and losses, which are primarily the result of remeasuring US dollar-denominated receivables and payables, are recorded in our Consolidated Statements of Operations and Other Comprehensive Loss. For the years ended March 31, 2018, 2017 and 2016, we recognized foreign currency translation losses of approximately $1,000, $11,000 and $0, respectively.

As of March 31, 2018, we realized $12,000 of cumulative foreign currency translation losses as Other Expense on the Consolidated Statement of Operations and Other Comprehensive Loss for the year ending March 31, 2018. No further foreign currency translation losses will be recorded as Organovo U.K., Ltd. operations have been combined with Organovo, Inc.’s operations.

Restricted cash

As of March 31, 2018 and 2017, the Company had approximately $127,000 of restricted cash, deposited with a financial institution. The entire amount is held in certificates of deposit to support a letter of credit agreement related to the Company’s facility lease.

Inventory

Inventories are stated at the lower of the cost or market (first-in, first-out). Inventory at March 31, 2018 consists of approximately $578,000 in raw materials, approximately $26,000 in work-in-process inventory, and approximately $238,000 in finished goods net of reserve. Inventory at March 31, 2017 consisted of approximately $467,000 in raw materials, approximately $83,000 in work-in progress inventory, and approximately $0 in finished goods.

Fixed assets and depreciation

Property and equipment are carried at cost. Expenditures that extend the life of the asset are capitalized and depreciated. Depreciation and amortization are provided using the straight-line method over the estimated useful lives of the related assets or, in the case of leasehold improvements, over the lesser of the useful life of the related asset or the remaining lease term. The estimated useful lives of the fixed assets range between one and seven years.

Impairment of long-lived assets

In accordance with authoritative guidance, the Company reviews its long-lived assets, including property and equipment and other assets, for impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be fully recoverable. To determine recoverability of its long-lived assets, the Company evaluates whether future undiscounted net cash flows will be less than the carrying amount of the assets and adjusts the carrying amount of its assets to fair value. Management has determined that no impairment of long-lived assets occurred as of March 31, 2018.

Fair value measurement

Financial assets and liabilities are measured at fair value, which is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The following is a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value:

•

Level 1 — Quoted prices in active markets for identical assets or liabilities.

•

Level 2 — Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

•

Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

The Company had issued warrants, of which some were classified as derivative liabilities as a result of the terms in the warrants that provide for down round protection in the event of a dilutive issuance. The Company used Level 3 inputs (unobservable inputs that are supported by little or no market activity, and that are significant to the fair value of the assets or liabilities) for its valuation methodology for the warrant derivative liabilities. The estimated fair values were determined using a Monte Carlo option pricing model based on various assumptions. The Company’s derivative liabilities were adjusted to reflect estimated fair value at each period end, with any increase or decrease in the estimated fair value being recorded in other income or expense accordingly, as adjustments to the fair value of the derivative liabilities. Various factors were considered in the pricing models the Company used to value the warrants, including the Company’s current stock price, the remaining life of the warrant, the volatility of the Company’s stock price, and the risk-free interest rate.

During the years ended March 31, 2017 and 2016, the Company valued its derivative liabilities in accordance with ASC 820. The remaining warrants expired as of March 31, 2017 and were removed from the Balance Sheet. The Company does not have any financial assets or liabilities measured on a fair value basis as of March 31, 2018.

The following table presents the activity for liabilities measured at estimated fair value using unobservable inputs for the years ended March 31, 2018 and 2017:

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)

	Warrant Derivative Liability (in thousands)
Balance at March 31, 2016	$	4
Issuances		—
Adjustments to estimated fair value		(4	)
Warrant liability removal due to settlements		—
Balance at March 31, 2017	$	—
Issuances		—
Adjustments to estimated fair value		—
Warrant liability removal due to settlements		—
Balance at March 31, 2018	$	—

Research and development

Research and development expenses, including direct and allocated expenses, consist of independent research and development costs, as well as costs associated with sponsored research and development. Research and development costs are expensed as incurred.

Income taxes

Deferred income taxes are recognized for the tax consequences in future years for differences between the tax basis of assets and liabilities and their financial reporting amounts at each year end based on enacted tax laws and statutory tax rates applicable to the periods in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized. Income tax expense is the combination of the tax payable for the year and the change during the year in deferred tax assets and liabilities.

Revenue recognition

The Company’s revenues are derived from research service agreements, product sales, and collaborative agreements with pharmaceutical and biotechnology companies, grants from the National Institutes of Health (“NIH”) and private not-for-profit organizations, and license-payments from academic institutions.

The Company recognizes revenue when the following criteria have been met: (i) persuasive evidence of an arrangement exists; (ii) services have been rendered or product has been delivered; (iii) price to the customer is fixed and determinable; and (iv) collection of the underlying receivable is reasonably assured.

Billings to customers or payments received from customers are included in deferred revenue on the balance sheet until all revenue recognition criteria are met. As of March 31, 2018 and 2017, the Company had approximately $687,000 and $640,000, respectively, in deferred revenue related to its commercial products and research service agreements, grants, and collaborative research programs.

Revenue arrangements with multiple deliverables

The Company follows ASC 605-25 Revenue Recognition – Multiple-Element Arrangements for revenue arrangements that contain multiple deliverables. Judgment is required to properly identify the accounting units of the multiple deliverable transactions and to determine the manner in which revenue should be allocated among the accounting units. Moreover, judgment is used in interpreting the commercial terms and determining when all criteria of revenue recognition have been met for each deliverable in order for revenue recognition to occur in the appropriate accounting period. For multiple deliverable agreements, consideration is allocated at the inception of the agreement to all deliverables based on their relative selling price. The relative selling price for each deliverable is determined using vendor-specific objective evidence (“VSOE”) of selling price or third-party evidence of selling price if VSOE does not exist. If neither VSOE nor third-party evidence of selling price exists, the Company uses its best estimate of the selling price for the deliverable.

While changes in the allocation of the arrangement consideration between the units of accounting will not affect the amount of total revenue recognized for a particular sales arrangement, any material changes in these allocations could impact the timing of revenue recognition, which could affect the Company’s results of operations.

The Company periodically receives license fees for non-exclusive research licensing associated with funded research projects. License fees under these arrangements are recognized over the term of the contract or development period as it has been determined that such licenses do not have stand-alone value.

Revenue from research service agreements

For research service agreements that contain only a single or primary deliverable, the Company defers any up-front fees collected from customers, and recognizes revenue for the delivered element only when it determines there are no uncertainties regarding customer acceptance. For agreements that contain multiple deliverables, the Company follows ASC 605-25 as described above.

Research and development revenue under collaborative agreements

The Company’s collaboration revenue consists of license and collaboration agreements that contain multiple elements, including non-refundable up-front fees, payments for reimbursement of third-party research costs, payments for ongoing research, payments associated with achieving specific development milestones and royalties based on specified percentages of net product sales, if any. The Company considers a variety of factors in determining the appropriate method of revenue recognition under these arrangements, such as whether the elements are separable, whether there are determinable fair values and whether there is a unique earnings process associated with each element of a contract.

The Company recognizes revenue from research funding under collaboration agreements when earned on a “proportional performance” basis as research services are provided or substantive milestones are achieved. The Company recognizes revenue that is contingent upon the achievement of a substantive milestone in its entirety in the period in which the milestone is achieved. A milestone is considered substantive when the consideration payable to us for the milestone (i) is consistent with our performance necessary to achieve the milestone or the increase in value to the collaboration resulting from our performance, (ii) relates solely to our past performance and (iii) is reasonable relative to all of the other deliverables and payments within the arrangement. In making this assessment, we consider all facts and circumstances relevant to the arrangement, including factors such as the risks that must be overcome to achieve the milestone, the level of effort and investment required to achieve the milestone and whether any portion of the milestone consideration is related to future performance or deliverables.

The Company initially defers revenue for any amounts billed or payments received in advance of the services being performed, and recognizes revenue pursuant to the related pattern of performance, using the appropriate method of revenue recognition based on its analysis of the related contractual element(s).

In November 2014, the Company entered into a collaborative nonexclusive research affiliation with a university medical school and a non-profit medical charity, under which the Company received a one-time grant from the charity towards the placement of a NovoGen Bioprinter^® at the university for the purpose of developing bioprinted tissues for surgical transplantation research. The Company completed its obligations under this agreement during the year ended March 31, 2017. The Company recorded approximately $0, $32,000, and $50,000 for the years ended March 31, 2018, 2017, and 2016, respectively, in revenue related to this collaboration in recognition of the proportional performance achieved.

In April 2015, the Company entered into a research collaboration agreement with a third party to develop custom tissue models for fixed fees. Based on the proportional performance achieved under this agreement for the years ended March 31, 2018, 2017, and 2016, the Company has recorded approximately $150,000, $117,000, and $352,000, respectively, in collaboration revenue. The Company has completed its obligations under this agreement as of March 31, 2018.

Also in April 2015, the Company entered into a multi-year research agreement with a third party to develop multiple custom tissue models for use in drug development. Approximately $0, $835,000, $80,000, under this agreement was recognized as revenue in recognition of the proportional performance achieved during the years ended March 31, 2018, 2017, and 2016, respectively.

In June 2016, the Company announced it had entered into another collaborative nonexclusive research affiliation with a university medical school and a non-profit medical charity, under which the Company received a one-time grant from the charity towards the placement of a NovoGen Bioprinter^® at the university for the purpose of developing bioprinted tissues for skeletal disease research. The Company received an up-front payment in June 2016, which has initially been recorded as deferred revenue. Revenues of $65,000 and $34,000 were recognized under this agreement during the years ended March 31, 2018 and 2017, respectively.

In December 2016, the Company signed another collaborative nonexclusive research affiliation with a university medical school and a non-profit medical charity, under which the Company received a one-time grant from the charity towards the placement of a NovoGen Bioprinter^® at the university for the purpose of developing an architecturally correct kidney for potential therapeutic applications. The Company received up-front payments in January and March of 2017, which has been recorded as deferred revenue. Revenues of $39,000 and $3,000 have been recorded under this agreement during the years ended March 31, 2018 and 2017, respectively.

In April 2017, the Company signed a collaborative non-exclusive research affiliation with a university, under which the Company received a one-time nonrefundable payment toward the placement of a NovoGen Bioprinter at the university for the purpose of specific research projects mutually agreed upon by the university and the Company in the field of volumetric muscle loss. The Company received an up-front payment in May 2017, which has been recorded as deferred revenue. Revenue of approximately $43,000 has been recorded during the year ended March 31, 2018, beginning subsequent to the installation of the printer in July of 2017. In addition, during April 2017, the Company signed a non-exclusive patent license agreement with the university including an annual fee of $75,000 for each of two years for the license to Company patents for research use limited to the field of volumetric muscle loss. The Company received the first annual payment of $75,000 in April 2017, which was initially recorded as deferred revenue. Revenue of $75,000 has been recorded under this agreement during the year ended March 31, 2018.

In September 2017, the Company entered into an agreement with a company, under which the Company received a one-time non-refundable payment of $50,000 for limited use of a Company patent in reference to four bioprinters developed and placed at research and academic facilities. The Company has recorded $50,000 in revenue during the year ended March 31, 2018.

Product revenue

The Company recognizes product revenue at the time of delivery to the customer or distributor, provided all other revenue recognition criteria have been met.

As our commercial sales increase, we expect to establish a reserve for estimated product returns that will be recorded as a reduction to revenue. That reserve will be maintained to account for future return of products sold in the current period. The reserve will be reviewed quarterly and will be estimated based on an analysis of our historical experience related to product returns.

Cost of revenue

The Company reported $1.0 million in cost of revenue for the years ended March 31, 2018 and 2017. Cost of revenues consists of our costs related to manufacturing and delivering our product and service revenue. Cost of revenue for the year ended March 31, 2016 was minimal and was included in research and development expense.

Grant revenues

During August of 2013, the Company was awarded a research grant by a private, not-for-profit organization for up to $251,700, contingent on go/no-go decisions made by the grantor at the completion of each stage of research as outlined in the grant award. Revenues from the grant are based upon internal costs incurred that are specifically covered by the grant, plus an additional rate that provides funding for overhead expenses. Revenue is recognized when the Company incurs expenses that are related to the grant. The Company completed its obligations under this agreement during the year ended March 31, 2017. Revenue recognized under this grant was approximately $0, $41,000 and $43,000 for the years ended March 31, 2018, 2017 and 2016, respectively.

During September of 2014, the NIH awarded the Company a research grant totaling approximately $222,000. Revenues from the grant are based upon internal costs incurred that are specifically covered by the grant, plus an additional rate that provides funding for overhead expenses. Revenue is recognized when the Company incurs expenses that are related to the grant. Revenue recognized under this grant was approximately $148,000 for the year ended 2016. The Company completed its obligations under this agreement during the year ended March 31, 2016.

During July 2017, the NIH awarded the Company a research grant totaling approximately $1,657,000. Revenues from the grant are based upon internal costs incurred that are specifically covered by the grant, plus an additional rate that provides funding for overhead expenses. Revenue is recognized when the Company incurs expenses that are related to the grant. Revenue recognized under this grant was approximately $554,000 during the year ended March 31, 2018.

Stock-based compensation

The Company accounts for stock-based compensation in accordance with the Financial Accounting Standards Board’s ASC Topic 718, Compensation — Stock Compensation, which establishes accounting for equity instruments exchanged for employee services. Under such provisions, stock-based compensation cost is measured at the grant date, based on the calculated fair value of the award, and is recognized as an expense, under the straight-line method, over the employee’s requisite service period (generally the vesting period of the equity grant).

The Company accounts for equity instruments, including restricted stock or stock options, issued to non-employees in accordance with authoritative guidance for equity based payments to non-employees. Stock options issued to non-employees are accounted for at their estimated fair value determined using the Black-Scholes option-pricing model. The fair value of options granted to non-employees is re-measured as they vest, and the resulting increase in value, if any, is recognized as expense during the period the related services are rendered. Restricted stock issued to non-employees is accounted for at its estimated fair value as it vests.

Comprehensive income (loss)

Comprehensive income (loss) is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources. The Company is required to record all components of comprehensive income (loss) in the financial statements in the period in which they are recognized. Net income (loss) and other comprehensive income (loss), including unrealized gains and losses on investments, are reported, net of their related tax effect, to arrive at comprehensive income (loss). For the years ended March 31, 2018, 2017 and 2016, the comprehensive loss was materially equal to the net loss, and consisted of net loss and foreign currency translation. As of March 31, 2018, unrealized foreign currency translation previously recorded in other comprehensive loss was realized and recorded to other expense.

Net loss per share

Basic and diluted net loss per share has been computed using the weighted-average number of shares of common stock outstanding during the period. The weighted-average number of shares used to compute diluted loss per share excludes any assumed exercise of stock options and warrants, shares reserved for purchase under the Company’s 2016 Employee Stock Purchase Plan (“ESPP”), the assumed release of restriction of restricted stock units, and shares subject to repurchase as the effect would be anti-dilutive. No dilutive effect was calculated for the years ended March 31, 2018, 2017 and 2016 as the Company reported a net loss for each respective period and the effect would have been anti-dilutive. Total common stock equivalents that were excluded from computing diluted net loss per share were approximately 12.6 million, 12.4 million, and 10.7 million for the years ended March 31, 2018, 2017 and 2016, respectively.

Fixed Assets

12 Months Ended

Mar. 31, 2018

Property Plant And Equipment [Abstract]

Fixed Assets

2. Fixed Assets

Fixed assets consisted of the following (in thousands):

	March 31, 2018			March 31, 2017
Laboratory equipment	$	3,695		$	3,727
Leasehold improvements		2,177			2,045
Computer software and equipment		656			656
Furniture and fixtures		319			319
Vehicles		9			9
		6,856			6,756
Less accumulated depreciation		(4,068	)		(2,916	)
	$	2,788		$	3,840

Depreciation expense for the years ended March 31, 2018, 2017 and 2016 was approximately $1,253,000, $1,139,000, and $805,000, respectively.

Accrued Expenses

12 Months Ended

Mar. 31, 2018

Payables And Accruals [Abstract]

Accrued Expenses

3. Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	March 31, 2018		March 31, 2017
Accrued compensation	$	2,735	$	3,318
Accrued legal and professional fees		99		572
Other accrued expenses		507		211
	$	3,341	$	4,101

Derivative Liability	12 Months Ended
Derivative Liability	Mar. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Liability	4. Derivative Liability During 2011 and 2012, the Company issued 22,847,182 five-year warrants to purchase the Company’s common stock in connection with financing transactions. The exercise price of the warrants was protected against down-round financing throughout the term of the warrants. Pursuant to ASC 815-15 and ASC 815-40, the fair value of the warrants was recorded as a derivative liability on the issuance dates. The Company revalued the warrants as of the end of each reporting period. There were no warrants classified as derivative liabilities outstanding as of March 31, 2018 or 2017. The change in fair value of the derivative liabilities for the year ended March 31, 2017 was a decrease of $4,000. The change in fair value of the derivative liabilities for the year ended March 31, 2016 was an increase of $17,000. These changes are included in other income (expense) in the statements of operations. During the years ended March 31, 2018 and 2017, no warrants classified as derivative liabilities were exercised. During the year ended March 31, 2017, 3,350 warrants expired. As of March 31, 2017, all warrants subject to derivative treatment were exercised or have expired.

Stockholders' Equity

12 Months Ended

Mar. 31, 2018

Equity [Abstract]

Stockholders' Equity

5. Stockholders’ Equity

Stock-based compensation expense and valuation information

Stock-based compensation expense for all stock awards consists of the following (in thousands):

	Year Ended March 31, 2018		Year Ended March 31, 2017		Year Ended March 31, 2016 (1)
Research and development	$	1,174	$	1,646	$	1,248
General and administrative	$	5,729	$	5,746	$	7,308
Total	$	6,903	$	7,392	$	8,556

(1)

Included in total stock-based compensation for the year ended March 31, 2016 is additional expense resulting from acceleration of the vesting schedule to fully vest options held by a terminated executive as pursuant to the 2012 Equity Incentive Plan. Additionally, as part of the severance agreement, a modification was made to extend the exercise period of the fully vested options, resulting in an incremental expense.

The total unrecognized compensation cost related to unvested stock option grants as of March 31, 2018 was approximately $5,650,000 and the weighted average period over which these grants are expected to vest is 2.42 years.

The total unrecognized stock-based compensation cost related to unvested restricted stock units (not including performance-based restricted stock units) as of March 31, 2018 was approximately $4,281,000, which will be recognized over a weighted average period of 2.76 years.

The total unrecognized stock-based compensation cost related to unvested performance-based restricted stock units as of March 31, 2018 was approximately $308,000, which will be recognized over a weighted average period of 2.00 years.

The total unrecognized stock-based compensation cost related to unvested employee stock purchase plan (“ESPP”) shares as of March 31, 2018 was approximately $19,000, which will be recognized over a period of 5 months.

The Company calculates the grant date fair value of all stock-based awards in determining the stock-based compensation expense. Stock-based awards include (i) stock options, (ii) restricted stock units, (iii) performance-based restricted stock units, and (iv) rights to purchase stock granted under the 2016 Employee Stock Purchase Plan (“ESPP”).

The Company uses the Black-Scholes valuation model to calculate the fair value of stock options. Stock-based compensation expense is recognized over the vesting period using the straight-line method. The fair value of stock options was estimated at the grant date using the following assumptions:

	Year Ended March 31, 2018			Year Ended March 31, 2017			Year Ended March 31, 2016
Dividend yield		—			—			—
Volatility		76.86	%		72.17	%		73.96	%
Risk-free interest rate		1.81	%		1.16	%		1.57	%
Expected life of options	6.00 years			6.00 years			6.00 years
Weighted average grant date fair value	$	1.73		$	2.41		$	2.52

The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. Due to the Company’s limited historical data, the estimated volatility incorporates the historical and implied volatility of comparable companies whose share prices are publicly available, in addition to our own. The risk-free interest rate assumption was based on the U.S. Treasury rates. The weighted average expected life of options was estimated using the average of the contractual term and the weighted average vesting term of the options. Certain options granted to consultants are subject to variable accounting treatment and are required to be revalued until vested.

The fair value of each restricted stock unit is recognized as stock-based compensation expense over the vesting term of the award. The fair value is based on the closing stock price on the date of the grant.

The Company uses the Black-Scholes valuation model to calculate the fair value of shares issued pursuant to the Company’s ESPP. Stock-based compensation expense is recognized over the purchase period using the straight-line method. The fair value of ESPP shares was estimated at the purchase period commencement date using the following weighted average assumptions:

	Year Ended March 31, 2018		Year Ended March 31, 2017
Dividend yield		—		—
Volatility	43.0% - 74.7%		72.9% - 74.7%
Risk-free interest rate	0.79% - 1.85%		0.47% - 0.79%
Expected term	6 months		6 months
Grant date fair value	$ 0.30 - $1.04		$ 1.04 - $1.22

The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. For the first full year of ESPP offering periods, beginning September 1, 2016, due to the Company’s limited historical data as an early-stage commercial business, the estimated volatility incorporates the historical and implied volatility of comparable companies whose share prices are publicly available. As of September 1, 2017 and the beginning of the second year of ESPP offering periods, the Company is using our Company-specific volatility rate. The risk-free interest rate assumption was based on U.S. Treasury rates. The expected life is the 6-month purchase period.

Preferred stock

The Company is authorized to issue 25,000,000 shares of preferred stock. There are no shares of preferred stock currently outstanding, and the Company has no present plans to issue shares of preferred stock.

Common stock

In May of 2008, the Board of Directors of the Company approved the 2008 Equity Incentive Plan (the “2008 Plan”). The 2008 Plan authorized the issuance of up to 1,521,584 common shares for awards of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock award units, and stock appreciation rights. The 2008 Plan terminates on July 1, 2018. No shares have been issued under the 2008 Plan since 2011, and the Company does not intend to issue any additional shares from the 2008 Plan in the future.

In January 2012, the Board of Directors of the Company approved the 2012 Equity Incentive Plan (the “2012 Plan”). The 2012 Plan authorized the issuance of up to 6,553,986 shares of common stock for awards of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units, performance units, performance shares, and other stock or cash awards. The Board of Directors and stockholders of the Company approved an amendment to the 2012 Plan in August 2013 to increase the number of shares of common stock that may be issued under the 2012 Plan by 5,000,000 shares. In addition, the Board of Directors and stockholders of the Company approved an amendment to the 2012 Plan in August 2015 to further increase the number of shares of common stock that may be issued under the 2012 Plan by 6,000,000 shares, bringing the aggregate shares issuable under the 2012 Plan to 17,553,986. The 2012 Plan as amended and restated became effective on August 20, 2015 and terminates ten years after such date. As of March 31, 2018, 4,595,021 shares remain available for issuance under the 2012 plan.

On April 24, 2017 the Company filed a Registration Statement on Form S-8 with the SEC authorizing the issuance of 2,297,034 shares of the Company’s Common Stock, pursuant to the terms of an Inducement Award Stock Option Agreement and an Inducement Award Performance-Based Restricted Stock Unit Agreement (collectively, the “Inducement Award Agreements”).

The Company filed a shelf registration statement on Form S-3 (File No. 333-189995), or the 2013 Shelf, with the SEC on July 17, 2013 authorizing the offer and sale in one or more offerings of up to $100,000,000 in aggregate of common stock, preferred stock, debt securities, or warrants to purchase common stock, preferred stock or debt securities, or any combination of the foregoing, either individually or as units comprised of one or more of the other securities. This 2013 Shelf was declared effective by the SEC on July 26, 2013.

A shelf registration statement on Form S-3 (File No. 333-202382), or the 2015 shelf, was filed with the SEC on February 27, 2015 authorizing the offer and sale in one or more offerings of up to $190,000,000 in aggregate of common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, or any combination of the foregoing, either individually or as units comprised of one or more of the other securities. The 2015 shelf was declared effective by the SEC on March 17, 2015.

In December 2014, the Company entered into an equity offering sales agreement (“2014 Sales Agreement”) with an investment banking firm. Under the terms of the sales agreement, the Company was eligible to offer and sell shares of its common stock, from time to time, through the investment bank in at-the-market offerings, as defined by the SEC, and pursuant to the Company’s 2013 Shelf. During the years ended March 31, 2018, 2017, and 2016, the Company issued 5,307,105, 997,181, and 0 shares of common stock in at-the-market offerings under the sales agreement with net proceeds of $9.2 million, $4.6, and $0 million, respectively. As of March 31, 2018, the Company had sold an aggregate of 7,304,286 shares of common stock in at-the-market offerings under the 2014 Sales Agreement, with net proceeds of approximately $19.9 million.

On July 20, 2016, the Company filed a prospectus supplement to move the remaining shares of common stock that previously could have been sold pursuant to the 2014 Sales Agreement under the 2013 Shelf to the 2015 Shelf. On the same date, the Company filed a post-effective amendment to the 2013 Shelf de-registering all remaining securities that could have been offered by the Company pursuant to the 2013 Shelf.

On June 18, 2015, the Company entered into an Underwriting Agreement with Jefferies LLC and Piper Jaffray & Co., acting as representatives of the underwriters named in the 2015 Underwriting Agreement and as joint book-running managers, relating to the issuance and sale of 9,425,000 shares of the Company’s common stock, par value $0.001 per share (the “2015 Offering”). The price to the public in the 2015 Offering was $4.25 per share, and the Underwriters agreed to purchase the shares from the Company pursuant to the 2015 Underwriting Agreement at a price of $3.995 per share. Under the terms of the 2015 Underwriting Agreement, the Company granted the Underwriters an option, exercisable for 30 days, to purchase up to an additional 1,413,750 shares. The Company issued 10,838,750 shares of common stock pursuant to the 2015 Underwriting Agreement, including shares issuable upon the exercise of the over-allotment option, with net proceeds of approximately $43.1 million, after deducting underwriting discounts and commissions and expenses payable by the Company. The shares were issued pursuant to the 2015 Shelf.

On October 25, 2016, the Company closed the issuance and sale of 10,065,000 shares (the “2016 Offering”) of its common stock. The 2016 Offering was effected pursuant to an Underwriting Agreement (the “2016 Underwriting Agreement”) with Jefferies LLC (the “Representative”), acting as representative of the underwriters named in the 2016 Underwriting Agreement. The price to the public in the 2016 Offering was $2.75 per share, and the underwriters purchased the shares from the Company pursuant to the 2016 Underwriting Agreement at a price of $2.585 per share. The net proceeds to the Company from the 2016 Offering were approximately $25.7 million after deducting underwriting discounts and commissions and expenses payable by the Company. The 2016 Offering was made pursuant to the Company’s 2015 Shelf.

The Company has an effective shelf registration statement on Form S-3 (File No. 333-222929) and the related prospectus previously declared effective by the Securities and Exchange Commission (the “SEC”) on February 22, 2018, as supplemented by a prospectus supplement, dated March 16, 2018 (the “2018 Shelf”), that expires on February 22, 2021. This replaces the 2015 Shelf which expired on March 17, 2018.

On March 16, 2018, the Company entered into a Sales Agreement (“2018 Sales Agreement”) with H.C. Wainwright & Co., LLC and Jones Trading Institutional Services LLC (each an “Agent” and together, the “Agents”), pursuant to which the Company may offer and sell, from time to time through the Agents, shares of its common stock in “at the market” sales transactions having an aggregate offering price of up to $50,000,000 (the “Shares”). Any shares offered and sold will be issued pursuant to the Company’s 2018 Shelf.

As of March 31, 2018, the Company cannot raise more than an aggregate of $100.0 million in future offerings under the 2018 Shelf including $50.0 million remaining for future issuance through its at-the-market program under the 2018 Sales Agreement. The Company intends to use the net proceeds raised through any at-the-market sales for general corporate purposes, general administrative expenses, and working capital and capital expenditures.

In addition, during the years ended March 31, 2018, 2017, and 2016, the Company issued 0, 700,379, and 32,914 shares of common stock upon exercise of 0, 822,903, and 43,796 warrants, respectively.

During the years ended March 31, 2018, 2017, and 2016, the Company issued 500,000, 245,271, and 116,001 shares of common stock upon exercise of 500,000, 245,271, and 116,001 stock options, respectively.

Restricted stock units

During the year ended March 31, 2018, the Company issued restricted stock units for an aggregate of 1,996,478 shares of common stock to its employees and directors. These shares of common stock will be issued upon vesting of the restricted stock units.

A summary of the Company’s restricted stock unit activity for the year ended March 31, 2018 is as follows:

	Number of Shares			Weighted Average Price
Unvested at March 31, 2017		1,178,114		$	3.57
Granted		1,996,478		$	2.59
Vested		(578,605	)	$	3.22
Canceled / forfeited		(560,642	)	$	2.91
Unvested at March 31, 2018		2,035,345		$	2.89

Performance-based restricted stock units

On April 24, 2017, the Company issued a Performance-Based Restricted Stock Unit Award for 208,822 shares of common stock (the “PBRSU”) to its newly hired Chief Executive Officer. The PBRSU was issued outside of the 2012 Plan, in the Inducement Award Agreement, as an “inducement award” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While outside the Company’s 2012 Plan, the terms and conditions of this award are consistent with awards granted to the Company’s executive officers pursuant to the 2012 Plan. On August 23, 2017, the Board of Directors formally approved the vesting criteria for the PBRSU. The vesting of the PBRSU is divided into five separate tranches each with independent vesting criteria. The first four tranches have performance criteria related to annual revenue goals with measurement at the end of fiscal year 2018 (20 percent), fiscal year 2019 (20 percent), fiscal year 2020 (20 percent), and fiscal year 2021 (20 percent). The fifth tranche has a performance metric related to a path to profitability goal measured as Negative Adjusted Earnings Before Interest, Taxes, Depreciation and Amortization (“EBITDA”) achievable at any point between the grant date and the end of fiscal year 2020 (20 percent). The number of units that ultimately vest for each tranche will range from 0 percent to 120 percent of the target amount, not to exceed 208,822 in aggregate. As of March 31, 2018, no tranches had vested, but 120% of the Negative Adjusted EBITDA tranche is expected to vest in a future year.

The grant date fair value of the PBRSU was $393,000 of which one-fifth is being recognized over each tranches’ service period. The Company began recording stock-based compensation expense for these tranches after the August 23, 2017 grant date when the financial performance goals were established and approved. As of March 31, 2018, the Negative Adjusted EBITDA tranche is expected to vest in the amount of 41,766 shares.

A summary of the Company’s performance-based restricted stock unit activity from March 31, 2017 through March 31, 2018 is as follows:

	Number of Shares			Maximum Number of Shares Eligible to be Issued			Weighted Average Price
Unvested at March 31, 2017		—			—		$	—
Awarded at target		208,822			208,822		$	1.88
Vested		—			—		$	—
Canceled / forfeited		(41,764	)		(8,352	)	$	1.88
Unvested at March 31, 2018		167,058			200,470		$	1.88

Stock options

During the year ended March 31, 2018 under the 2012 Equity Incentive Plan, 281,956 stock options were issued at various exercise prices.

In addition, on April 24, 2017, the Company granted a stock option for 2,088,212 shares of common stock to its newly hired Chief Executive Officer. This stock option award was issued outside of the 2012 Plan, in the Inducement Award Agreement, as an “inducement award” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While granted outside the Company’s 2012 Plan, the terms and conditions of this stock option award are consistent with awards granted to the Company’s executive officers pursuant to the 2012 Plan.

The following table summarizes stock option activity for the year ended March 31, 2018:

	Options Outstanding			Weighted- Average Exercise Price		Aggregate Intrinsic Value
Outstanding at March 31, 2017		10,956,201		$	4.63	$	4,876,437
Options granted		2,370,168		$	2.64	$	—
Options canceled		(2,694,057	)	$	5.78	$	—
Options exercised		(500,000	)	$	1.65	$	235,000
Outstanding at March 31, 2018		10,132,312		$	4.01	$	591,082
Vested and Exercisable at March 31, 2018		6,211,427		$	4.54	$	591,082

The weighted-average remaining contractual term of stock options exercisable and outstanding at March 31, 2018 was approximately 5.91 years.

Employee Stock Purchase Plan

In June 2016, our Board of Directors adopted, and in August 2016 stockholders subsequently approved, the 2016 Employee Stock Purchase Plan (“ESPP”). We reserved 1,500,000 shares of common stock for issuance thereunder. The ESPP permits employees after five months of service to purchase common stock through payroll deductions, limited to 15 percent of each employee’s compensation up to $25,000 per employee per year or 10,000 shares per employee per purchase period. Shares under the ESPP are purchased at 85 percent of the fair market value at the lower of (i) the closing price on the first trading day of the six-month purchase period or (ii) the closing price on the last trading day of the six-month purchase period. The initial offering period commenced in September 2016. During the year ended March 31, 2018, 162,340 shares were issued under the ESPP. At March 31, 2018, there were 1,285,103 shares remaining available for the purchase under the ESPP.

Warrants

During the years ended December 31, 2012 and 2011, the Company issued warrants to investors to purchase 21,347,182 and 2,909,750 shares, respectively, of its common stock.

During the years ended March 31, 2018, 2017 and 2016, 0, 353,093 and 0 of these warrants were exercised for cash proceeds of approximately $0, $336,000 and $0, respectively, and 0, 469,000 and 43,796 of these warrants were exercised through a cashless exercise for issuance of 0, 347,286 and 32,914 shares of common stock, respectively.

In 2012, the Company issued a total of 650,000 warrants to purchase common stock, in connection with consulting agreements, at prices ranging from $1.70 to $3.24, with lives ranging from two to five years, to be earned over service periods of up to six months. During the years ended March 31, 2018, 2017, and 2016, no warrants held by consultants were exercised. As of March 31, 2018, 220,000 of these warrants are outstanding.

Additionally, during September 2014, the Company issued 50,000 warrants to a consultant in recognition of services previously provided. These warrants were classified as equity instruments because they do not contain any anti-dilution provisions. As of December 31, 2014, the full amount of the warrants related to these services, approximately $237,000 had been recognized.

In November 2014, in connection with a consulting agreement, the Company issued 145,000 warrants to purchase common stock, at a price of $6.84, with a life of five years, to be earned over a seventeen month service period ended on March 31, 2016. The final number of vested warrant shares was 95,000, based on management’s judgment of the satisfaction of specific performance metrics. The fair value of the warrants was estimated to be approximately $74,000, which was revalued and amortized over the term of the consulting agreement. These warrants were classified as equity instruments because they do not contain any anti-dilution provisions. The Black-Scholes model, using a volatility rate of 73.4% and a risk-free interest rate factor of 1.21%, was used to determine the value as of March 31, 2016. The Company recognized approximately $6,000 during the year ended March 31, 2016 related to these services. As of March 31, 2016, these warrants were fully expensed.

The following table summarizes warrant activity for the year ended March 31, 2018:

	Warrants			Weighted-Average Exercise Price
Balance at March 31, 2017		221,370		$	7.16
Granted		—			—
Expired / Canceled		(1,370	)	$	2.28
Exercised		—			—
Balance at March 31, 2018		220,000		$	7.19

The warrants outstanding at March 31, 2018 are immediately exercisable at prices between $6.84 and $7.62 per share, and have a weighted average remaining term of approximately 1.21 years.

Common stock reserved for future issuance

Common stock reserved for future issuance consisted of the following at March 31, 2018:

Common stock warrants outstanding			220,000
Common stock options outstanding under the 2008 Plan			622,192
Common stock options outstanding under the 2012 Plan			7,421,908
Common stock reserved under the 2012 Plan			4,595,021
Common stock reserved under the 2016 Employee Stock Purchase Plan			1,285,103
Restricted stock units outstanding under the 2012 Plan			2,035,345
Common stock options outstanding and reserved under the Incentive Award Agreement			2,088,212
Restricted stock units outstanding under the Incentive Award Agreement			200,470
Total			18,468,251

Commitments and Contingencies

12 Months Ended

Mar. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

6. Commitments and Contingencies

Operating leases

Since July 2012, the Company has leased its main facilities at 6275 Nancy Ridge Drive, San Diego, CA 92121. The lease, as amended in 2013, 2015 and 2016, consists of approximately 45,580 rentable square feet containing laboratory, clean room and office space. Monthly rental payments are currently approximately $120,000 per month with 3% annual escalators. The lease term for 14,685 of the total rentable square footage expires on December 15, 2018, with the remainder of the rentable square footage expiring on September 1, 2021, with the Company having an option to terminate this lease on or after September 1, 2019.

From February 1, 2015 through January 31, 2018 the Company leased a second facility consisting of 5,803 rentable square feet of office and lab space located at 6310 Nancy Ridge Drive, San Diego, CA 92121, with a monthly rent of $12,000, which increased by 3% each 12-month anniversary of the 36 month lease.

The Company also previously leased a third facility from February 1, 2016 through January 31, 2017, consisting of 12,088 rentable square feet of office space located at 6166 Nancy Ridge Drive, San Diego, California 92121 with a monthly rent of $15,000.

The Company records rent expense on a straight-line basis over the life of the leases and records the excess of expense over the amounts paid as deferred rent. In addition, one of the leases provides for certain improvements made for the Company’s benefit to be funded by the landlord. Such costs, totaling approximately $518,000 to date, have been capitalized as fixed assets and included in deferred rent.

Rent expense was approximately $1,458,000, $1,295,000, and $1,088,000 for the years ended March 31, 2018, 2017 and 2016, respectively.

Future minimum rental payments required under operating leases that have initial or remaining non-cancelable lease terms in excess of one year as of March 31, 2018, are as follows (in thousands):

Fiscal year ended March 31, 2019		1,385
Fiscal year ended March 31, 2020		1,073
Fiscal year ended March 31, 2021		1,104
Fiscal year ended March 31, 2022		468
Fiscal year ended March 31, 2023		—
Thereafter		—
Total	$	4,030

Legal matters

In addition to commitments and obligations in the ordinary course of business, the Company may be subject, from time to time, to various claims and pending and potential legal actions arising out of the normal conduct of its business. The Company assesses contingencies to determine the degree of probability and range of possible loss for potential accrual in its financial statements. Because litigation is inherently unpredictable and unfavorable resolutions could occur, assessing litigation contingencies is highly subjective and requires judgments about future events. When evaluating contingencies, the Company may be unable to provide a meaningful estimate due to a number of factors, including the procedural status of the matter in question, the presence of complex or novel legal theories, and/or the ongoing discovery and development of information important to the matters. In addition, damage amounts claimed in litigation against it may be unsupported, exaggerated or unrelated to possible outcomes, and as such are not meaningful indicators of its potential liability.

The Company regularly reviews contingencies to determine the adequacy of its accruals and related disclosures. During the period presented, the Company has not recorded any accrual for loss contingencies associated with such claims or legal proceedings; determined that an unfavorable outcome is probable or reasonably possible; or determined that the amount or range of any possible loss is reasonably estimable. However, the outcome of legal proceedings and claims brought against the Company is subject to significant uncertainty. Therefore, although management considers the likelihood of such an outcome to be remote, if one or more of these legal matters were resolved against the Company in a reporting period, the Company’s consolidated financial statements for that reporting period could be materially adversely affected.

Licensing Agreements and Research Contracts

12 Months Ended

Mar. 31, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

Licensing Agreements and Research Contracts

7. Licensing Agreements and Research Contracts

University of Missouri

In March 2009, the Company entered into a license agreement with the Curators of the University of Missouri to in-license certain technology and intellectual property relating to self-assembling cell aggregates and to intermediate cellular units. The Company received the exclusive worldwide rights to commercialize products comprising this technology for all fields of use. The Company is required to pay the University of Missouri royalties ranging from 1% to 3% of net sales of covered tissue products, and of the fair market value of covered tissues transferred internally for use in the Company’s commercial service business, depending on the level of net sales achieved by the Company each year. The Company paid a minimum annual royalty of $25,000 in January 2017 for the calendar year 2017 and of $25,000 in January 2018 for the calendar year 2018, which is credited against royalties due during the subsequent twelve months. The license agreement terminates upon expiration of the patents licensed and is subject to certain conditions as defined in the license agreement, which are expected to expire after 2029.

In March 2010, the Company entered into a license agreement with the Curators of the University of Missouri to in-license certain technology and intellectual property relating to engineered biological nerve grafts. The Company received the exclusive worldwide rights to commercialize products comprising this technology for all fields of use. The Company is required to pay the University of Missouri royalties ranging from 1% to 3% of net sales of covered tissue products depending on the level of net sales achieved by the Company each year. The license agreement terminates upon expiration of the patents licensed and is subject to certain conditions as defined in the license agreement.

Clemson University

In May 2011, the Company entered into a license agreement with Clemson University Research Foundation to in-license certain technology and intellectual property relating to ink-jet printing of viable cells. The Company received the exclusive worldwide rights to commercialize products comprising this technology for all fields of use. The Company is required to pay the University royalties ranging from 1.5% to 3% of net sales of covered tissue products and the fair market value of covered tissues transferred internally for use in the Company’s commercial service business, depending on the level of net sales reached each year. The license agreement terminates upon expiration of the patents licensed, which is expected to expire in May 2024, and is subject to certain conditions as defined in the license agreement. Minimum annual royalty payments of $20,000 were due for each of the two years beginning with calendar 2014, and $40,000 per year beginning with calendar 2016. The annual minimum royalty is creditable against royalties owed during the same calendar year.

Capitalized license fees consisted of the following (in thousands):

	March 31, 2018			March 31, 2017
License fees	$	218		$	148
Less accumulated amortization		(67	)		(53	)
License fees, net	$	151		$	95

The above license fees, net of accumulated amortization, are included in Other Assets in the accompanying balance sheets and are being amortized over the life of the related patents. Amortization expense of licenses was approximately $13,600, $10,300, and $9,700 for the years ended March 31, 2018, 2017 and 2016, respectively. At March 31, 2018, the weighted average remaining amortization period for all licenses was approximately 12 years. The annual amortization expense of licenses for the next five years is estimated to be approximately $14,300 per year.

Income Taxes

12 Months Ended

Mar. 31, 2018

Income Tax Disclosure [Abstract]

Income Taxes

8. Income Taxes

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s net deferred tax assets are as follows as of March 31, 2018, March 31, 2017, and March 31, 2016 (in thousands):

	March 31, 2018			March 31, 2017			March 31, 2016
Deferred tax assets:
Net operating loss carry forwards	$	—		$	—		$	—
Research and development credits		—			—			—
Depreciation and amortization		25			(71	)		(105	)
Accrued expenses and reserves		1,050			1,373			862
Stock compensation		3,753			6,720			5,584
Other, net		8			7			12
Total deferred tax assets		4,836			8,029			6,353
Valuation allowance		(4,836	)		(8,029	)		(6,353	)
	$	—		$	—		$	—

A full valuation allowance has been established to offset the deferred tax assets as management cannot conclude that realization of such assets is more likely than not. Under the Internal Revenue Code (“IRC”) Sections 382 and 383, annual use of our net operating loss and research tax credit carryforwards to offset taxable income may be limited based on cumulative changes in ownership. We have not completed an analysis to determine whether any such limitations have been triggered as of March 31, 2018. Until this analysis is completed, we have removed the deferred tax assets related to net operating losses and research credits from our deferred tax asset schedule. Further, until a study is completed and any limitation known, no amounts are being considered as an uncertain tax position or disclosed as an unrecognized tax benefit. Due to the existence of the valuation allowance, future changes in the Company’s unrecognized tax benefits will not impact its effective tax rate. Any carryforwards that will expire prior to utilization as a result of such limitations will be removed from deferred tax assets with a corresponding reduction of the valuation allowance. The valuation allowance decreased by approximately $3,193,000 and increased by approximately $1,676,000 for the years ended March 31, 2018 and 2017, respectively.

The Company had federal, state, and foreign net operating loss carryforwards of approximately $146,320,000 and $78,034,000, respectively, as of March 31, 2018. The federal and state net operating loss carryforwards (“NOLs”) will begin to expire in 2028, unless previously utilized.

In March 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Updated No. 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). The Company adopted ASU 2016-09 on April 1, 2017. Under the new guidance, companies will no longer record excess tax benefits and certain tax deficiencies related to share-based payments to employees in additional paid in capital. Instead, the Company will recognize all income tax effects of awards in its income statement when awards vest or are settled. All excess tax benefits not previously recognized were to be recorded to retained earnings as a cumulative effect adjustment upon adoption. No adjustment to retained earnings was necessary upon adoption; however, as the Company has removed the deferred tax assets related to net operating losses from its deferred tax asset schedule as well as the Company’s valuation allowance position. Approximately $2,331,000 attributable to excess tax benefits on stock compensation that had not previously been recognized would have been added to the deferred tax asset for NOLs with a corresponding increase to the valuation allowance.

The Company had federal and state research tax credit carryforwards of approximately $3,404,000 and $3,105,000 at March 31, 2018 and March 31, 2017, respectively. The federal research tax credit carryforwards begin expiring in 2028. The state research tax credit carryforwards do not expire.

The Tax Cuts and Jobs Act (“the Act”) was enacted on December 22, 2017. The Act (i) reduces the US federal corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, (ii) generally reduces a company’s ability to utilize accumulated net operating losses, an (iii) requires the calculation of a one-time transition tax on certain previously unrepatriated foreign earnings and profits (“E&P”). The Act also impacts the valuation of a company’s deferred tax assets and liabilities. In accordance with Staff Accounting Bulletin No. 118, as of March 31, 2018, we have not completed our accounting for the tax effects of enactment of the Act; however, in certain cases, as described below, we have made a reasonable estimate of the effects on our existing deferred tax balances and the one-time transition tax. In other cases, we have not been able to make a reasonable estimate and continue to account for those items based on our existing accounting under ASC 740, Income Taxes, and the provisions of the tax laws that were in effect immediately prior to the enactment. For the items for which we were able to determine a reasonable estimate, we recognized a provisional amount of $2.7 million. In all cases, we will continue to refine our calculations as additional analysis is completed. In addition, our estimates may also be affected as we gain a more thorough understanding of the tax law.

Deferred tax assets and liabilities: We remeasured certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21%. However, we are still analyzing certain aspects of the Act and refining our calculations, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. The provisional amount recorded related to the remeasurement of our deferred tax balance was $2,700,000, which was fully offset by a decrease in our valuation allowance.

Foreign tax effects: The one-time transition tax is based on the total post-1986 earnings and profits (E&P) previously deferred from US income taxes. The Company has a deficit in post-1986 E&P from its foreign subsidiary resulting in no increase to income tax expense. No amounts have been provided for any additional outside basis difference inherent in this entity, as these amounts continue to be indefinitely reinvested in foreign operations.

In 2009, the Company adopted the accounting guidance for uncertainty in income taxes pursuant to ASC 740-10. The adoption of this guidance did not have a material impact on the Company’s consolidated financial statements. The Company did not record any accruals for income tax accounting uncertainties for the year ended March 31, 2018.

The Company’s policy is to recognize interest and penalties that would be assessed in relation to the settlement value of unrecognized tax benefits as a component of income tax expense. The Company did not accrue either interest or penalties from inception through March 31, 2018.

The Company does not expect its unrecognized tax benefits to significantly increase or decrease within the next 12 months.

The Company is subject to tax in the United States, in various state jurisdictions, and in the United Kingdom. As of March 31, 2018, the Company’s tax years from inception are subject to examination by the tax authorities due to the generation of net operating losses. The Company is not currently under examination by any jurisdiction.

Concentrations	12 Months Ended
Concentrations	Mar. 31, 2018
Risks And Uncertainties [Abstract]
Concentrations	9. Concentrations Credit risk and significant customers Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of temporary cash investments. The Company maintains cash balances at various financial institutions primarily located within the United States. Accounts at these institutions are secured by the Federal Deposit Insurance Corporation. Balances may exceed federally insured limits. The Company has not experienced losses in such accounts, and management believes that the Company is not exposed to any significant credit risk with respect to its cash and cash equivalents. The Company is also potentially subject to concentrations of credit risk in its revenues and accounts receivable. Because it is in the early commercial stage, the Company’s revenues to date have been derived from a relatively small number of customers and collaborators. However, the Company has not historically experienced any accounts receivable write-downs and management does not believe significant credit risk exists as of March 31, 2018.

Related Parties	12 Months Ended
Related Parties	Mar. 31, 2018
Related Party Transactions [Abstract]
Related Parties	10. Related Parties The Company has entered into two agreements with related parties in the ordinary course of its business and on terms and conditions it believes are as fair as those it offers and receives from independent third parties. Each agreement was ratified by the Company’s Board of Directors or a committee thereof pursuant to its related party transaction policy. In August 2017, the Company entered into a services agreement with Cirius Tx, Inc., an entity for which Robert Baltera, Jr., a director of the Company, serves as Chief Executive Officer. Under this agreement and its amendments, the Company has provided ExVive™ Liver Tissue Services for Cirius amounting to $161,000 recognized as revenue in the year ended March 31, 2018. The agreement contains another $7,000 of ExVive™ Liver Tissue Services to be completed in the first quarter of fiscal 2019. In November 2017, the Company entered into a collaboration agreement with Viscient Biosciences, an entity for which Keith Murphy, a former director and former Chief Executive Officer of the Company, serves as Chief Executive Officer. Under this agreement, the parties intend to develop a custom research platform for studying liver disease. The Company expects the platform to expand its current service portfolio for compound screening in disease models, which aids the drug discovery work for other customers. Viscient intends to target early discovery work for non-alcoholic fatty liver disease (“NAFLD”) and non-alcoholic steatohepatitis (“NASH”). Under this agreement and its amendments, the Company provided research services to Viscient amounting to $358,000 recognized as revenue in the year ended March 31, 2018. Additionally, Viscient purchased primary human cell-based products from our subsidiary, Samsara, in the amount of $13,500 recognized as revenue in the year ended March 31, 2018.

Defined Contribution Plan	12 Months Ended
Defined Contribution Plan	Mar. 31, 2018
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
Defined Contribution Plan	11. Defined Contribution Plan The Company has a defined contribution 401(k) plan covering substantially all employees. During the year ended March 31, 2015, the 401(k) plan was amended (the “Amended Plan”) to include an employer matching provision. Under the terms of the Amended Plan, the Company will make matching contributions on up to the first 6% of compensation contributed by its employees. Amounts expensed under the Company’s 401(k) plan for the years ended March 31, 2018, 2017, and 2016 were approximately $337,000, $352,000, and $277,000, respectively.

Recent Accounting Pronouncements	12 Months Ended
Recent Accounting Pronouncements	Mar. 31, 2018
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	12. Recent Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard was originally effective for public companies for annual reporting periods beginning after December 15, 2016, with no early application permitted. In August 2015, the FASB issued ASU No. 2015-14 that defers by one year the effective date for all entities, with application permitted as of the original effective date. The updated standard becomes effective for us on April 1, 2018. The standard permits the use of either the retrospective or cumulative effect transition method. The Company adopted the new standard for the fiscal year beginning April 1, 2018 using the modified retrospective application method. The Company has substantially completed its assessment of the new standard and the Company believes that there will not be a material impact on its financial statements or disclosures. In February 2016, the FASB issued ASU 2016-02, Leases, which requires an entity to recognize lease assets and lease liabilities on the balance sheet for leases with terms of more than 12 months and to disclose key information about leasing arrangements. This new guidance is effective for us on April 1, 2019, with early adoption permitted in any interim or annual period. The Company is currently evaluating the impact that this guidance will have on its financial statements and related disclosures. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718), which requires an entity recognize excess tax benefits and deficiencies as income tax expense or benefit, the cash flows of which should be included as operating activity in the statement of cash flows. An entity is allowed to either continue accruing compensation cost based on expected forfeitures or to begin recognizing expense as forfeitures occur. In addition, an entity may withhold the maximum statutory tax, increasing the allowable cash settlement portion of awards. The cash paid by an employer when directly withholding shares for tax purposes should be included in the financing activity section of the statement of cash flows. This new guidance was effective for us on April 1, 2017. The requirements of ASU 2016-09 did not have a significant impact on our consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Compensation - Stock Compensation: Scope of Modification Accounting, which provides clarity and guidance around which changes to the terms or conditions of a stock-based payment award require an entity to apply modification accounting in Topic 718. The standard is effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual reporting periods. The adoption of this guidance will have no impact on our financial statements unless we have modification accounting in accordance with Topic 718. In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception. These amendments simplify the accounting for certain financial instruments with down round features. The amendments require companies to disregard the down round feature when assessing whether the instrument is indexed to its own stock, for purposes of determining liability or equity classification. Companies that provide earnings per share (EPS) data will adjust their basic EPS calculation for the effect of the feature when triggered (i.e., when the exercise price of the related equity-linked financial instrument is adjusted downward because of the down round feature) and will also recognize the effect of the trigger within equity. This standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The adoption of this guidance will have no impact on our financial statements as the Company’s only derivative liabilities were all exercised or expired as of March 31, 2017 and were removed from the Balance Sheet. In December 2017, the United States (“U.S.”) enacted the Tax Cuts and Jobs Act (the “Act”), which changes existing U.S. tax law and includes various provisions that are expected to affect public companies. The Act (i) reduces the US federal corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, (ii) generally reduces a company’s ability to utilize accumulated net operating losses, and (iii) requires the calculation of a one-time transition tax on certain previously unrepatriated foreign earnings and profits (“E&P”). The Act also impacts the valuation of a company’s deferred tax assets and liabilities. In accordance with Staff Accounting Bulletin No. 118, as of March 31, 2018, we have not completed our accounting for the tax effects of enactment of the Act; however, in certain cases we have made a reasonable estimate of the effects on our existing deferred tax balances and the one-time transition tax. In other cases, we have not been able to make a reasonable estimate and continue to account for those items based on our existing accounting under ASC 740, Income Taxes, and the provisions of the tax laws that were in effect immediately prior to the enactment. For the items for which we were able to determine a reasonable estimate, we recognized a provisional amount of $2.7 million. In all cases, we will continue to refine our calculations as additional analysis is completed. In addition, our estimates may also be affected as we gain a more thorough understanding of the tax law.

Quarterly Financial Data (unaudited)

12 Months Ended

Mar. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (unaudited)

13. Quarterly Financial Data (unaudited)

The following quarterly financial data, in the opinion of management, fairly presents the results for the periods presented (in thousands, except per share data):

	Year Ended March 31, 2018
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Revenue	$	990		$	1,355		$	1,153		$	1,105
Net loss		(10,102	)		(9,461	)		(7,791	)		(7,449	)
Net loss per common share - basic and diluted		(0.10	)		(0.09	)		(0.07	)		(0.07	)
Weighted average shares used in computing net loss per common share—basic and diluted		104,689,391			106,297,699			107,345,623			110,690,335


	Year Ended March 31, 2017
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Revenue	$	891		$	1,376		$	1,151		$	812
Net loss		(8,767	)		(9,442	)		(9,581	)		(10,657	)
Net loss per common share - basic and diluted		(0.09	)		(0.10	)		(0.09	)		(0.10	)
Weighted average shares used in computing net loss per common share—basic and diluted		92,391,964			93,185,400			101,174,734			104,385,617

Subsequent Events	12 Months Ended
Subsequent Events	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events On April 17, 2018, the Company undertook the second phase of its business restructuring to better focus and align resources, reducing approximately 13 positions, or 15% of its overall workforce. This second phase of restructuring allows the Company to improve its operational efficiency, consolidate overlapping positions, and streamline its management structure. As a result, the Company expects to record a restructuring charge in the fiscal first quarter of approximately $0.4 million, primarily related to employee severance and benefits costs. The actions associated with the restructuring announcement are anticipated to be complete by the end of fiscal first quarter 2019, with liabilities anticipated to be paid by the end of fiscal fourth quarter 2019.

Description of Business and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Nature of Operations and Basis of Presentation

Nature of operations and basis of presentation

Liquidity

Based on its current operating plan and available cash resources, the Company believes it has sufficient resources to fund its business for at least the next twelve months.

Use of estimates

Financial instruments

Cash and cash equivalents

The Company considers all highly liquid investments with original maturities of 90 days or less to be cash equivalents.

Derivative financial instruments

Foreign Currency

Restricted cash

Inventory

Fixed assets and depreciation

Impairment of long-lived assets

Fair value measurement

•

Level 1 — Quoted prices in active markets for identical assets or liabilities.

•

Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

The following table presents the activity for liabilities measured at estimated fair value using unobservable inputs for the years ended March 31, 2018 and 2017:

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)

	Warrant Derivative Liability (in thousands)
Balance at March 31, 2016	$	4
Issuances		—
Adjustments to estimated fair value		(4	)
Warrant liability removal due to settlements		—
Balance at March 31, 2017	$	—
Issuances		—
Adjustments to estimated fair value		—
Warrant liability removal due to settlements		—
Balance at March 31, 2018	$	—

Research and development

Income taxes

Revenue recognition

Revenue arrangements with multiple deliverables

Revenue from research service agreements

Research and development revenue under collaborative agreements

Product revenue

The Company recognizes product revenue at the time of delivery to the customer or distributor, provided all other revenue recognition criteria have been met.

Cost of revenues

Cost of revenue

Grant revenues

Stock-based compensation

Comprehensive income (loss)

Net loss per share

Description of Business and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Activity for Liabilities Measured at Estimated Fair Value Using Unobservable Inputs

The following table presents the activity for liabilities measured at estimated fair value using unobservable inputs for the years ended March 31, 2018 and 2017:

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)

	Warrant Derivative Liability (in thousands)
Balance at March 31, 2016	$	4
Issuances		—
Adjustments to estimated fair value		(4	)
Warrant liability removal due to settlements		—
Balance at March 31, 2017	$	—
Issuances		—
Adjustments to estimated fair value		—
Warrant liability removal due to settlements		—
Balance at March 31, 2018	$	—

Fixed Assets (Tables)

12 Months Ended

Mar. 31, 2018

Property Plant And Equipment [Abstract]

Schedule of Fixed Assets

Fixed assets consisted of the following (in thousands):

	March 31, 2018			March 31, 2017
Laboratory equipment	$	3,695		$	3,727
Leasehold improvements		2,177			2,045
Computer software and equipment		656			656
Furniture and fixtures		319			319
Vehicles		9			9
		6,856			6,756
Less accumulated depreciation		(4,068	)		(2,916	)
	$	2,788		$	3,840

Accrued Expenses (Tables)

12 Months Ended

Mar. 31, 2018

Payables And Accruals [Abstract]

Summary of Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	March 31, 2018		March 31, 2017
Accrued compensation	$	2,735	$	3,318
Accrued legal and professional fees		99		572
Other accrued expenses		507		211
	$	3,341	$	4,101

Stockholders' Equity (Tables)

12 Months Ended

Mar. 31, 2018

Class Of Stock [Line Items]

Schedule of Stock-based Compensation Expense

Stock-based compensation expense for all stock awards consists of the following (in thousands):

	Year Ended March 31, 2018		Year Ended March 31, 2017		Year Ended March 31, 2016 (1)
Research and development	$	1,174	$	1,646	$	1,248
General and administrative	$	5,729	$	5,746	$	7,308
Total	$	6,903	$	7,392	$	8,556

Fair Value of Employee Stock Options

The fair value of stock options was estimated at the grant date using the following assumptions:

	Year Ended March 31, 2018			Year Ended March 31, 2017			Year Ended March 31, 2016
Dividend yield		—			—			—
Volatility		76.86	%		72.17	%		73.96	%
Risk-free interest rate		1.81	%		1.16	%		1.57	%
Expected life of options	6.00 years			6.00 years			6.00 years
Weighted average grant date fair value	$	1.73		$	2.41		$	2.52

Fair Value of Employee Stock Purchase Plan

The fair value of ESPP shares was estimated at the purchase period commencement date using the following weighted average assumptions:

	Year Ended March 31, 2018		Year Ended March 31, 2017
Dividend yield		—		—
Volatility	43.0% - 74.7%		72.9% - 74.7%
Risk-free interest rate	0.79% - 1.85%		0.47% - 0.79%
Expected term	6 months		6 months
Grant date fair value	$ 0.30 - $1.04		$ 1.04 - $1.22

Summary of Stock Option Activity

The following table summarizes stock option activity for the year ended March 31, 2018:

	Options Outstanding			Weighted- Average Exercise Price		Aggregate Intrinsic Value
Outstanding at March 31, 2017		10,956,201		$	4.63	$	4,876,437
Options granted		2,370,168		$	2.64	$	—
Options canceled		(2,694,057	)	$	5.78	$	—
Options exercised		(500,000	)	$	1.65	$	235,000
Outstanding at March 31, 2018		10,132,312		$	4.01	$	591,082
Vested and Exercisable at March 31, 2018		6,211,427		$	4.54	$	591,082

Summary of Warrant Activity

The following table summarizes warrant activity for the year ended March 31, 2018:

	Warrants			Weighted-Average Exercise Price
Balance at March 31, 2017		221,370		$	7.16
Granted		—			—
Expired / Canceled		(1,370	)	$	2.28
Exercised		—			—
Balance at March 31, 2018		220,000		$	7.19

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consisted of the following at March 31, 2018:

Common stock warrants outstanding			220,000
Common stock options outstanding under the 2008 Plan			622,192
Common stock options outstanding under the 2012 Plan			7,421,908
Common stock reserved under the 2012 Plan			4,595,021
Common stock reserved under the 2016 Employee Stock Purchase Plan			1,285,103
Restricted stock units outstanding under the 2012 Plan			2,035,345
Common stock options outstanding and reserved under the Incentive Award Agreement			2,088,212
Restricted stock units outstanding under the Incentive Award Agreement			200,470
Total			18,468,251

Restricted stock units (RSUs) [Member]

Class Of Stock [Line Items]

Summary of Company's Restricted Stock Unit Activity and Performance Based Restricted Stock Unit Activity

A summary of the Company’s restricted stock unit activity for the year ended March 31, 2018 is as follows:

	Number of Shares			Weighted Average Price
Unvested at March 31, 2017		1,178,114		$	3.57
Granted		1,996,478		$	2.59
Vested		(578,605	)	$	3.22
Canceled / forfeited		(560,642	)	$	2.91
Unvested at March 31, 2018		2,035,345		$	2.89

Performance-Based Restricted Stock Units [Member]

Class Of Stock [Line Items]

Summary of Company's Restricted Stock Unit Activity and Performance Based Restricted Stock Unit Activity

A summary of the Company’s performance-based restricted stock unit activity from March 31, 2017 through March 31, 2018 is as follows:

	Number of Shares			Maximum Number of Shares Eligible to be Issued			Weighted Average Price
Unvested at March 31, 2017		—			—		$	—
Awarded at target		208,822			208,822		$	1.88
Vested		—			—		$	—
Canceled / forfeited		(41,764	)		(8,352	)	$	1.88
Unvested at March 31, 2018		167,058			200,470		$	1.88

Commitments and Contingencies (Tables)

12 Months Ended

Mar. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

Future Minimum Rental Payments Required under Operating Leases that have Initial or Remaining Non-Cancelable Lease Terms in Excess of One Year

Future minimum rental payments required under operating leases that have initial or remaining non-cancelable lease terms in excess of one year as of March 31, 2018, are as follows (in thousands):

Fiscal year ended March 31, 2019		1,385
Fiscal year ended March 31, 2020		1,073
Fiscal year ended March 31, 2021		1,104
Fiscal year ended March 31, 2022		468
Fiscal year ended March 31, 2023		—
Thereafter		—
Total	$	4,030

Licensing Agreements and Research Contracts (Tables)

12 Months Ended

Mar. 31, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Capitalized License Fees

Capitalized license fees consisted of the following (in thousands):

	March 31, 2018			March 31, 2017
License fees	$	218		$	148
Less accumulated amortization		(67	)		(53	)
License fees, net	$	151		$	95

Income Taxes (Tables)

12 Months Ended

Mar. 31, 2018

Income Tax Disclosure [Abstract]

Summary of Net Deferred Tax Assets

Significant components of the Company’s net deferred tax assets are as follows as of March 31, 2018, March 31, 2017, and March 31, 2016 (in thousands):

	March 31, 2018			March 31, 2017			March 31, 2016
Deferred tax assets:
Net operating loss carry forwards	$	—		$	—		$	—
Research and development credits		—			—			—
Depreciation and amortization		25			(71	)		(105	)
Accrued expenses and reserves		1,050			1,373			862
Stock compensation		3,753			6,720			5,584
Other, net		8			7			12
Total deferred tax assets		4,836			8,029			6,353
Valuation allowance		(4,836	)		(8,029	)		(6,353	)
	$	—		$	—		$	—

Quarterly Financial Data (unaudited) (Tables)

12 Months Ended

Mar. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Data

The following quarterly financial data, in the opinion of management, fairly presents the results for the periods presented (in thousands, except per share data):

	Year Ended March 31, 2018
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Revenue	$	990		$	1,355		$	1,153		$	1,105
Net loss		(10,102	)		(9,461	)		(7,791	)		(7,449	)
Net loss per common share - basic and diluted		(0.10	)		(0.09	)		(0.07	)		(0.07	)
Weighted average shares used in computing net loss per common share—basic and diluted		104,689,391			106,297,699			107,345,623			110,690,335


	Year Ended March 31, 2017
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Revenue	$	891		$	1,376		$	1,151		$	812
Net loss		(8,767	)		(9,442	)		(9,581	)		(10,657	)
Net loss per common share - basic and diluted		(0.09	)		(0.10	)		(0.09	)		(0.10	)
Weighted average shares used in computing net loss per common share—basic and diluted		92,391,964			93,185,400			101,174,734			104,385,617

Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	1 Months Ended					12 Months Ended
	Sep. 30, 2017	Jul. 31, 2017	Apr. 30, 2017	Sep. 30, 2014	Aug. 31, 2013	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents						$ 43,726,000	$ 62,751,000	$ 62,091,000	$ 50,142,000
Accumulated deficit						(234,120,000)	(199,317,000)
Cash flow from operations						$ 28,857,000	$ 29,185,000	29,368,000
Issuance of common stock						111,032,957	104,551,466
Foreign currency translation adjustment						$ (1,000)	$ (11,000)	0
Cumulative foreign currency translation losses						(12,000)
Restricted cash						127,000	127,000
Inventory of raw materials, net of reserves						578,000	467,000
Inventory of work-in-process, net of reserves						26,000	83,000
Inventory of finished goods, net of reserves						$ 238,000	0
Estimated useful life of the fixed assets						The estimated useful lives of the fixed assets range between one and seven years.
Impairment of long-lived assets						$ 0
Warrants expiration date						Mar. 31, 2017
Deferred revenue						$ 668,000	582,000
Cost of revenues						1,030,000	956,000	0
Revenue recognized under grants						554,000	41,000	191,000
Dilutive effect						$ 0	$ 0	$ 0
Common stock equivalents excluded from computing diluted net loss per share						12,600,000	12,400,000	10,700,000
NIH Research Grants Two [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue recognized under grants				$ 222,000
Revenue recognized under grants								$ 148,000
NIH Research Grants Three [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue recognized under grants		$ 1,657,000
Revenue recognized under grants						$ 554,000
Private, Not-for-Profit Organization [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue recognized under grants						0	$ 41,000	43,000
Research and Development Services [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Deferred revenue						687,000	640,000
Research and Development Services Four [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract						150,000	117,000	352,000
Research and Development Services Five [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract						0	835,000	80,000
Research and Development Services Six [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract						0	32,000	$ 50,000
Research and Development Services Seven [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract						65,000	34,000
Research and Development Services Eight [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract						39,000	$ 3,000
Research and Development Services Ten [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract						43,000
Research and Development Services Eleven [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract						75,000
Non-exclusive patent license agreement annual fee			$ 75,000
Non-exclusive patent license agreement term			2 years
Proceeds from Non-exclusive patent annual license fee			$ 75,000
Research and Development Services Nine [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue related to research contract	$ 50,000					$ 50,000
Maximum [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Maturity of highly liquid investment						90 days
Useful life of fixed assets, range						7 years
Maximum [Member] \| Private, Not-for-Profit Organization [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue recognized under grants					$ 251,700
Minimum [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful life of fixed assets, range						1 year
At-The-Market Facility [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock						5,307,105
Gross proceeds from sale of common stock shares						$ 9,200,000

Description of Business and Summary of Significant Accounting Policies - Activity for Liabilities Measured at Estimated Fair Value Using Unobservable Inputs (Detail) - Significant Other Unobservable Inputs (Level 3) [Member] - Warrants [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Warrant Derivative Liability, Beginning balance	$ 0	$ 4
Issuances	0	0
Adjustments to estimated fair value	0	(4)
Warrant liability removal due to settlements	0	0
Warrant Derivative Liability, Ending balance	$ 0	$ 0

Fixed Assets - Schedule of Fixed Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Laboratory equipment	$ 3,695	$ 3,727
Leasehold improvements	2,177	2,045
Computer software and equipment	656	656
Furniture and fixtures	319	319
Vehicles	9	9
Fixed assets, gross	6,856	6,756
Less accumulated depreciation	(4,068)	(2,916)
Fixed assets, net	$ 2,788	$ 3,840

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Payables And Accruals [Abstract]
Accrued compensation	$ 2,735	$ 3,318
Accrued legal and professional fees	99	572
Other accrued expenses	507	211
Accrued expenses	$ 3,341	$ 4,101

Derivative Liability - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2014	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2012	Mar. 31, 2011
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Warrants issued					22,847,182	22,847,182
Warrants maturity term	5 years				5 years	5 years
Outstanding derivative liabilities		0	0
Change in fair value of warrant liabilities		$ 0	$ (4)	$ 17
Exercised derivative liabilities		0	0
Warrants expired			3,350

Stockholders' Equity - Schedule of Stock-based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 6,903	$ 7,392	$ 8,556
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,174	1,646	1,248
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 5,729	$ 5,746	$ 7,308

Stockholders' Equity - Stock-based Compensation Expense and Valuation Information - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2018 USD ($)
Class Of Stock [Line Items]
Total unrecognized compensation cost related to unvested stock option grants	$ 5,650,000
Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Total unrecognized compensation cost related, weighted average period	5 months
Unrecognized stock-based compensation expense	$ 19,000
Stock options [Member]
Class Of Stock [Line Items]
Total unrecognized compensation cost related, weighted average period	2 years 5 months 1 day
Restricted stock units (RSUs) [Member]
Class Of Stock [Line Items]
Total unrecognized compensation cost related, weighted average period	2 years 9 months 3 days
Unrecognized stock-based compensation expense	$ 4,281,000
Performance-Based Restricted Stock Units [Member]
Class Of Stock [Line Items]
Total unrecognized compensation cost related, weighted average period	2 years
Unrecognized stock-based compensation expense	$ 308,000

Stockholders' Equity - Fair Value of Employee Stock Options (Detail) - $ / shares	1 Months Ended	12 Months Ended
	Nov. 30, 2014	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Dividend yield		0.00%	0.00%	0.00%
Volatility	73.40%	76.86%	72.17%	73.96%
Risk-free interest rate	1.21%	1.81%	1.16%	1.57%
Expected life of options		6 years	6 years	6 years
Weighted average grant date fair value		$ 1.73	$ 2.41	$ 2.52

Stockholders' Equity - Fair Value of Employee Stock Purchase Plan (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Expected term	6 years	6 years	6 years
Grant date fair value	$ 1.73	$ 2.41	$ 2.52
2016 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0.00%	0.00%
Volatility, Minimum	43.00%	72.90%
Volatility, Maximum	74.70%	74.70%
Risk-free interest rate, Minimum	0.79%	0.47%
Risk-free interest rate, Maximum	1.85%	0.79%
Expected term	6 months	6 months
2016 Employee Stock Purchase Plan [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value	$ 0.30	$ 1.04
2016 Employee Stock Purchase Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value	$ 1.04	$ 1.22

Stockholders' Equity - Preferred Stock - Additional Information (Detail)	Mar. 31, 2018 shares
Equity [Abstract]
Preferred stock, shares authorized	25,000,000
Preferred stock, shares outstanding	0

Stockholders' Equity - Common Stock - Additional Information (Detail) - USD ($)			12 Months Ended			40 Months Ended
	Oct. 25, 2016	Jun. 18, 2015	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2018	Mar. 16, 2018	Apr. 24, 2017	Aug. 31, 2015	Feb. 27, 2015	Aug. 31, 2013	Jul. 17, 2013	Jan. 31, 2012	May 31, 2008
Class Of Stock [Line Items]
Issuance of common stock from stock options exercises, net, Shares			500,000	245,271	116,001
Issuance of common stock			111,032,957	104,551,466		111,032,957
Common stock, par value			$ 0.001	$ 0.001		$ 0.001
Issuance of common stock from warrant exercises, net, Shares			0	700,379	32,914
Warrants exercised			0	822,903	43,796
Stock option exercised			500,000	245,271	116,001
Equity Offering Sales Agreement [Member]
Class Of Stock [Line Items]
Issuance of common stock from stock options exercises, net, Shares			5,307,105	997,181	0
Value of shares sold under equity distribution agreement			$ 9,200,000	$ 4,600,000	$ 0	$ 19,900,000
Issuance of common stock			7,304,286			7,304,286
2015 Underwriting Agreement [Member]
Class Of Stock [Line Items]
Stock option exercisable, period		30 days
Additional common stock issued on exercise of option by underwriters		1,413,750
2018 Sales Agreement [Member]
Class Of Stock [Line Items]
Equity sales agreement expiration date			Feb. 22, 2021
2018 Sales Agreement [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Common stock value reserved for future issuance			$ 100,000,000			$ 100,000,000
IPO [Member]
Class Of Stock [Line Items]
Securities authorized for offer and sale, amount										$ 190,000,000		$ 100,000,000
Secondary Offering [Member] \| 2015 Underwriting Agreement [Member]
Class Of Stock [Line Items]
Issuance of common stock from stock options exercises, net, Shares		10,838,750
Common stock, par value		$ 0.001
Offering price per share		$ 4.25
Gross proceeds from sale of common stock shares		$ 43,100,000
Secondary Offering [Member] \| 2016 Underwriting Agreement [Member]
Class Of Stock [Line Items]
Offering price per share	$ 2.75
Gross proceeds from sale of common stock shares	$ 25,700,000
Over Allotment Option [Member] \| 2015 Underwriting Agreement [Member]
Class Of Stock [Line Items]
Issuance of common stock		9,425,000
Sale of stock price per share net of fees		$ 3.995
Over Allotment Option [Member] \| 2016 Underwriting Agreement [Member]
Class Of Stock [Line Items]
Issuance of common stock	10,065,000
Sale of stock price per share net of fees	$ 2.585
At The Market [Member]
Class Of Stock [Line Items]
Issuance of common stock			5,307,105			5,307,105
Gross proceeds from sale of common stock shares			$ 9,200,000
At The Market [Member] \| 2018 Sales Agreement [Member]
Class Of Stock [Line Items]
Common stock value reserved for future issuance			$ 50,000,000			$ 50,000,000
At The Market [Member] \| 2018 Sales Agreement [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Common stock value reserved for future issuance							$ 50,000,000
Equity Incentive Plan 2008 [Member]
Class Of Stock [Line Items]
Common shares authorized to be issued														1,521,584
Termination date of equity incentive plan			Jul. 01, 2018
Shares issued during the year			0
Equity Incentive Plan 2012 [Member]
Class Of Stock [Line Items]
Common shares authorized to be issued									6,000,000		5,000,000		6,553,986
Shares available for issuance			4,595,021			4,595,021			17,553,986
Termination period of Equity Incentive Plan			10 years
Inducement Award Agreements [Member]
Class Of Stock [Line Items]
Common shares authorized to be issued								2,297,034

Stockholders' Equity - Restricted Stock Units and Performance-Based Restricted Stock Units - Additional Information (Detail)		12 Months Ended
	Aug. 23, 2017 USD ($) Tranche shares	Mar. 31, 2018 Tranche shares	Apr. 24, 2017 shares	Mar. 31, 2017 shares
Restricted stock units (RSUs) [Member]
Class Of Stock [Line Items]
Restricted stock awards granted		1,996,478
Number of shares allocated		2,035,345		1,178,114
Inducement Award Performance-Based Restricted Stock Units [Member]
Class Of Stock [Line Items]
Number of tranches \| Tranche	5
Number of tranches vested \| Tranche		0
Grant date fair value of stock units \| $	$ 393,000
Stock units expected to vest		41,766
Inducement Award Performance-Based Restricted Stock Units [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Number of shares allocated	208,822
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche One [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2018
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche One [Member] \| Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche One [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Two [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2019
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Two [Member] \| Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Two [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Three [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2020
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Three [Member] \| Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Three [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share Based Compensation Award Tranche Four [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2021
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share Based Compensation Award Tranche Four [Member] \| Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share Based Compensation Award Tranche Four [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share Based Compensation Award Tranche Five [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2020
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share Based Compensation Award Tranche Five [Member] \| Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Share Based Compensation Award Tranche Five [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| Future Year [Member]
Class Of Stock [Line Items]
Award vesting percentage		120.00%
Inducement Award Performance-Based Restricted Stock Units [Member] \| CEO [Member]
Class Of Stock [Line Items]
Number of shares allocated			208,822

Stockholders' Equity - Summary of Company's Restricted Stock Unit Activity and Performance Based Restricted Stock Unit Activity (Detail)	12 Months Ended
	Mar. 31, 2018 $ / shares shares
Restricted stock units (RSUs) [Member]
Class Of Stock [Line Items]
Beginning balance, Unvested, Number of Shares	1,178,114
Granted/Awarded at target, Number of Shares	1,996,478
Vested, Number of Shares	(578,605)
Canceled / forfeited, Number of Shares	(560,642)
Ending balance, Unvested, Number of Shares	2,035,345
Beginning balance, Unvested, Weighted Average Price \| $ / shares	$ 3.57
Granted/Awarded at target, Weighted Average Price \| $ / shares	2.59
Vested, Weighted Average Price \| $ / shares	3.22
Canceled / forfeited, Weighted Average Price \| $ / shares	2.91
Ending balance, Unvested, Weighted Average Price \| $ / shares	$ 2.89
Performance-Based Restricted Stock Units [Member]
Class Of Stock [Line Items]
Beginning balance, Unvested, Number of Shares	0
Granted/Awarded at target, Number of Shares	208,822
Vested, Number of Shares	0
Canceled / forfeited, Number of Shares	(41,764)
Ending balance, Unvested, Number of Shares	167,058
Beginning balance, Unvested, Weighted Average Price \| $ / shares	$ 0
Granted/Awarded at target, Weighted Average Price \| $ / shares	1.88
Vested, Weighted Average Price \| $ / shares	0
Canceled / forfeited, Weighted Average Price \| $ / shares	1.88
Ending balance, Unvested, Weighted Average Price \| $ / shares	$ 1.88
Beginning balance, Unvested, Maximum Number of Shares Eligible to be Issued	0
Awarded at target, Maximum Number of Shares Eligible to be Issued	208,822
Vested, Maximum Number of Shares Eligible to be Issued	0
Forfeited, Maximum Number of Shares Eligible to be Issued	(8,352)
Ending balance, Unvested, Maximum Number of Shares Eligible to be Issued	200,470

Stockholders' Equity - Stock Options and Employee Stock Purchase Plan - Additional Information (Detail) - USD ($)		12 Months Ended
	Apr. 24, 2017	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Class Of Stock [Line Items]
Issuances of common stock from stock option exercises, Shares		500,000	245,271	116,001
Weighted-average remaining contractual term of stock options exercisable		5 years 10 months 28 days
Weighted-average remaining contractual term of stock options outstanding		5 years 10 months 28 days
Number of common stock shares approved under ESPP		18,468,251
Expected life of options		6 years	6 years	6 years
Shares issued under ESPP		162,340
2012 Plan [Member]
Class Of Stock [Line Items]
Issuances of common stock from stock option exercises, Shares		281,956
Inducement Award Agreement [Member] \| CEO [Member]
Class Of Stock [Line Items]
Stock options granted	2,088,212
2016 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Number of common stock shares approved under ESPP		1,500,000
Employee subscription rate		15.00%
Compensation amount per employee		$ 25,000
Number of shares per employee		10,000
Fair market value at discount		85.00%
Purchase period		6 months
Initial offering period		2016-09
Description of plan		Shares under the ESPP are purchased at 85 percent of the fair market value at the lower of (i) the closing price on the first trading day of the six-month purchase period or (ii) the closing price on the last trading day of the six-month purchase period.
Expected life of options		6 months	6 months
Shares remaining available for purchase under ESPP		1,285,103

Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Beginning balance	10,956,201
Granted, Options Outstanding	2,370,168
Canceled, Options Outstanding	(2,694,057)
Exercised, Options Outstanding	(500,000)	(245,271)	(116,001)
Options Outstanding, Ending balance	10,132,312	10,956,201
Vested and Exercisable, Options Outstanding	6,211,427
Weighted-Average Exercise Price, Options Beginning balance	$ 4.63
Options granted, Weighted-Average Exercise Price	2.64
Options canceled, Weighted-Average Exercise Price	5.78
Options exercised, Weighted-Average Exercise Price	1.65
Weighted-Average Exercise Price, Options Ending balance	4.01	$ 4.63
Vested and Exercisable, Weighted-Average Exercise Price	$ 4.54
Aggregate Intrinsic Value, Options Beginning balance	$ 4,876,437
Options Exercised, Aggregate Intrinsic Value	235,000
Aggregate Intrinsic Value, Options Ending balance	591,082	$ 4,876,437
Vested and Exercisable, Aggregate Intrinsic Value	$ 591,082

Stockholders' Equity - Warrants - Additional Information (Detail) - USD ($)		1 Months Ended		12 Months Ended
	Dec. 31, 2014	Nov. 30, 2014	Sep. 30, 2014	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Class Of Stock [Line Items]
Purchase shares of common stock for issued warrants							21,347,182			2,909,750
Cash proceeds from warrant exercises						$ 139,000
Warrants to purchase common stock		145,000		220,000			650,000
Warrants maturity term		5 years						5 years	5 years
Warrants issued			50,000
Warrants earned, service period		17 months
Number of warrant shares vested upon satisfaction of specific performance metrics				95,000
Volatility		73.40%		76.86%	72.17%	73.96%
Risk-free interest rate		1.21%		1.81%	1.16%	1.57%
Weighted-average remaining contractual term of options exercisable				5 years 10 months 28 days
Consultation Service Agreement September 2014
Class Of Stock [Line Items]
Recognized expenses of warrants	$ 237,000
Consultation Service Agreement November 2014
Class Of Stock [Line Items]
Recognized expenses of warrants						$ 6,000
Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share				$ 6.84
Warrants maturity term							2 years
Maximum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share				$ 7.62
Warrants maturity term							5 years
Warrants [Member]
Class Of Stock [Line Items]
Number of warrants exercised				0	353,093	0
Cash proceeds from warrant exercises				$ 0	$ 336,000	$ 0
Number of warrant exercised through cashless				0	469,000	43,796
Cashless exercise in exchange for issuance of common stock				0	347,286	32,914
Warrants exercisable price, per share		$ 6.84
Estimated fair value of warrants		$ 74,000
Weighted-average remaining contractual term of options exercisable				1 year 2 months 15 days
Warrants [Member] \| Consultants [Member]
Class Of Stock [Line Items]
Number of warrants exercised				0	0	0
Warrants [Member] \| Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share							$ 1.70
Warrants [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share							$ 3.24

Stockholders' Equity - Summary of Warrant Activity (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Beginning balance	10,956,201
Granted, Options Outstanding	2,370,168
Expired / Canceled, Options Outstanding	(2,694,057)
Exercised, Options Outstanding	(500,000)	(245,271)	(116,001)
Options Outstanding, Ending balance	10,132,312	10,956,201
Weighted-Average Exercise Price, Options Beginning balance	$ 4.63
Granted, Weighted-Average Exercise Price	2.64
Expired / Canceled, Weighted-Average Exercise Price	5.78
Exercised, Weighted-Average Exercise Price	1.65
Weighted-Average Exercise Price, Options Ending balance	$ 4.01	$ 4.63
Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Beginning balance	221,370
Granted, Options Outstanding	0
Expired / Canceled, Options Outstanding	(1,370)
Exercised, Options Outstanding	0
Options Outstanding, Ending balance	220,000	221,370
Weighted-Average Exercise Price, Options Beginning balance	$ 7.16
Granted, Weighted-Average Exercise Price	0
Expired / Canceled, Weighted-Average Exercise Price	2.28
Exercised, Weighted-Average Exercise Price	0
Weighted-Average Exercise Price, Options Ending balance	$ 7.19	$ 7.16

Stockholders' Equity - Common Stock Reserved for Future Issuance (Detail)	Mar. 31, 2018 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	18,468,251
Equity Incentive Plan 2012 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	4,595,021
2016 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	1,500,000
Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	220,000
Stock options [Member] \| Equity Incentive Plan 2008 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	622,192
Stock options [Member] \| Equity Incentive Plan 2012 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	7,421,908
Stock options [Member] \| 2016 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	1,285,103
Stock options [Member] \| Inducement Award Agreement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	2,088,212
Restricted stock units (RSUs) [Member] \| Equity Incentive Plan 2012 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	2,035,345
Restricted stock units (RSUs) [Member] \| Inducement Award Agreement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	200,470

Commitments and Contingencies - Additional Information (Detail)		12 Months Ended			36 Months Ended	69 Months Ended
	Dec. 28, 2015 USD ($) ft²	Mar. 31, 2018 USD ($) ft²	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Jan. 31, 2018 USD ($) ft²	Mar. 31, 2018 USD ($)
Commitments And Contingencies [Line Items]
Rent expense per month		$ 120,000
Base rent escalators		3.00%			3.00%	3.00%
Office space under lease agreement \| ft²		45,580
Area of leased office space \| ft²	12,088				5,803
Lease term					36 months
Lease rental period start date	Feb. 01, 2016				Feb. 01, 2015
Lease rental period end date	Jan. 31, 2017				Jan. 31, 2018
Base rent under the lease	$ 15,000				$ 12,000
Leasehold improvements				$ 374,000		$ 518,000
Rent expense		$ 1,458,000	$ 1,295,000	$ 1,088,000
Lease Term For Remainder of Rentable Square Footage [Member]
Commitments And Contingencies [Line Items]
Lease expiration date		Sep. 01, 2021
Lease option termination description		option to terminate this lease on or after September 1, 2019
Lease Term For 14,685 of Total Rentable Square Footage [Member]
Commitments And Contingencies [Line Items]
Office space under lease agreement \| ft²		14,685
Lease expiration date		Dec. 15, 2018

Commitments and Contingencies - Future Minimum Rental Payments Required under Operating Leases that have Initial or Remaining Non-Cancelable Lease Terms in Excess of One Year (Detail) $ in Thousands	Mar. 31, 2018 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Fiscal year ended March 31, 2019	$ 1,385
Fiscal year ended March 31, 2020	1,073
Fiscal year ended March 31, 2021	1,104
Fiscal year ended March 31, 2022	468
Fiscal year ended March 31, 2023	0
Thereafter	0
Total	$ 4,030

Licensing Agreements and Research Contracts - Additional Information (Detail) - USD ($)	1 Months Ended					12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	May 31, 2011	Mar. 31, 2010	Mar. 31, 2009	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Licensing Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense of licenses						$ 13,600	$ 10,300	$ 9,700
Weighted average remaining amortization period for all licenses						12 years
Annual amortization expense of licenses year 1						$ 14,300
Annual amortization expense of licenses year 2						14,300
Annual amortization expense of licenses year 3						14,300
Annual amortization expense of licenses year 4						14,300
Annual amortization expense of licenses year 5						$ 14,300
University of Missouri [Member]
Finite-Lived Intangible Assets [Line Items]
Royalty fees percentage minimum				1.00%	1.00%
Royalty fees percentage maximum				3.00%	3.00%
Minimum annual royalty paid	$ 25,000	$ 25,000
Expected expiration year of license agreement					2029
Clemson University [Member]
Finite-Lived Intangible Assets [Line Items]
Minimum annual royalty payment due								$ 40,000	$ 20,000	$ 20,000
Clemson University [Member] \| Licensing Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Royalty fees percentage minimum			1.50%
Royalty fees percentage maximum			3.00%
Expected expiration year of license agreement			2024-05

Licensing Agreements and Research Contracts - Schedule of Capitalized License Fees (Detail) - Licensing Agreements [Member] - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
License fees	$ 218	$ 148
Less accumulated amortization	(67)	(53)
License fees, net	$ 151	$ 95

Income Taxes - Summary of Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Deferred tax assets:
Net operating loss carry forwards	$ 0	$ 0	$ 0
Research and development credits	0	0	0
Depreciation and amortization	25	(71)	(105)
Accrued expenses and reserves	1,050	1,373	862
Stock compensation	3,753	6,720	5,584
Other, net	8	7	12
Total deferred tax assets	4,836	8,029	6,353
Valuation allowance	(4,836)	(8,029)	(6,353)
Deferred tax assets net	$ 0	$ 0	$ 0

Income Taxes - Additional Information (Detail) - USD ($)		3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 01, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits		$ 0		$ 0
Increase (decrease) in valuation allowance				(3,193,000)	$ 1,676,000
Federal net operating loss carryforwards		146,320,000		146,320,000
State net operating loss carryforwards		$ 78,034,000		$ 78,034,000
Federal and state net operating loss carryforwards (“NOLs”) expiring year				2028
Federal research tax credit carryforwards expiration period				2028
Federal statutory tax rate		21.00%	35.00%
Recognized a provisional amount				$ 2,700,000
Valuation allowance for deferred tax				(2,700,000)
Accrued expense regarding interest or penalties		$ 0		0
Federal [Member]
Operating Loss Carryforwards [Line Items]
Research tax credit carryforwards		3,404,000		3,404,000	3,105,000
State [Member]
Operating Loss Carryforwards [Line Items]
Research tax credit carryforwards		$ 3,404,000		$ 3,404,000	$ 3,105,000
Accounting Standards Update 2016-09 [Member]
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance	$ 2,331,000
Adjustment to retained earnings	0
Unrecognized excess tax benefits	$ 2,331,000

Related Parties - Additional Information (Detail)	3 Months Ended	12 Months Ended
Related Parties - Additional Information (Detail)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($) Agreement
Related Party Transaction [Line Items]
Number of related parties agreement entered \| Agreement		2
Cirius Tx, Inc., [Member]
Related Party Transaction [Line Items]
Revenue recognized from related parties agreement		$ 161,000
Cirius Tx, Inc., [Member] \| Scenario, Forecast [Member]
Related Party Transaction [Line Items]
Amount of transactions with related party for providing services	$ 7,000
Viscient Biosciences [Member]
Related Party Transaction [Line Items]
Revenue recognized from related parties agreement		358,000
Viscient Biosciences [Member] \| Samsara [Member] \| Primary Human Cell-based Products [Member]
Related Party Transaction [Line Items]
Revenue recognized from related parties agreement		$ 13,500

Recent Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2018
Accounting Changes And Error Corrections [Abstract]
Federal statutory tax rate	21.00%	35.00%
Recognized a provisional amount			$ 2.7

Quarterly Financial Data (unaudited) - Schedule of Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 1,105	$ 1,153	$ 1,355	$ 990	$ 812	$ 1,151	$ 1,376	$ 891	$ 4,603	$ 4,230	$ 1,483
Net loss	$ (7,449)	$ (7,791)	$ (9,461)	$ (10,102)	$ (10,657)	$ (9,581)	$ (9,442)	$ (8,767)	$ (34,803)	$ (38,447)	$ (38,575)
Net loss per common share - basic and diluted	$ (0.07)	$ (0.07)	$ (0.09)	$ (0.10)	$ (0.10)	$ (0.09)	$ (0.10)	$ (0.09)	$ (0.32)	$ (0.39)	$ (0.43)
Weighted average shares used in computing net loss per common share—basic and diluted	110,690,335	107,345,623	106,297,699	104,689,391	104,385,617	101,174,734	93,185,400	92,391,964	107,243,974	97,763,032	90,057,356

Subsequent Events - Additional Information (Detail) $ in Millions		3 Months Ended
	Apr. 17, 2018 Position	Jun. 30, 2018 USD ($)
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of positions reduced \| Position	13
Percentage of overall workforce reduced	15.00%
Scenario, Forecast [Member] \| Employee Severance and Benefits Costs [Member]
Subsequent Event [Line Items]
Restructuring charge \| $		$ 0.4

Defined Contribution Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
Percentage of employees contribution	6.00%
Administration expenses	$ 337,000	$ 352,000	$ 277,000

Consolidated Statements of Cash Flows (Parenthetical) - USD ($)	12 Months Ended	69 Months Ended
	Mar. 31, 2016	Mar. 31, 2018
Statement Of Cash Flows [Abstract]
Warrant liability reduced	$ 139,000
Leasehold improvements	$ 374,000	$ 518,000