Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Sep. 30, 2018	Nov. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	ONVO
Entity Registrant Name	ORGANOVO HOLDINGS, INC.
Entity Central Index Key	0001497253
Current Fiscal Year End Date	--03-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		115,890,335

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Current Assets
Cash and cash equivalents	$ 37,355	$ 43,726
Accounts receivable	475	883
Grant receivable	453	145
Inventory, net	1,036	842
Prepaid expenses and other current assets	798	1,164
Total current assets	40,117	46,760
Fixed assets, net	2,236	2,788
Restricted cash	127	127
Other assets, net	145	152
Total assets	42,625	49,827
Current Liabilities
Accounts payable	449	464
Accrued expenses	2,026	3,341
Deferred revenue	619	668
Deferred rent	197	185
Total current liabilities	3,291	4,658
Deferred revenue, net of current portion	0	19
Deferred rent, net of current portion	464	564
Total liabilities	3,755	5,241
Commitments and Contingencies	0	0
Stockholders’ Equity
Common stock, $0.001 par value; 200,000,000 shares authorized, 115,200,421 and 111,032,957 shares issued and outstanding at September 30, 2018 and March 31, 2018, respectively	115	111
Additional paid-in capital	286,128	278,595
Accumulated deficit	(247,373)	(234,120)
Total stockholders’ equity	38,870	44,586
Total Liabilities and Stockholders’ Equity	$ 42,625	$ 49,827

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Mar. 31, 2018
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	115,200,421	111,032,957
Common stock, shares outstanding	115,200,421	111,032,957

Unaudited Condensed Consolidated Statements of Operations and Other Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Total Revenues	$ 943	$ 1,355	$ 1,632	$ 2,345
Cost of revenues	125	254	245	555
Research and development expenses	3,187	4,944	6,566	9,977
Selling, general and administrative expenses	3,640	5,736	8,407	11,592
Total costs and expenses	6,952	10,934	15,218	22,124
Loss from Operations	(6,009)	(9,579)	(13,586)	(19,779)
Other Income (Expense)
Gain (loss) on fixed asset disposals	0	0	2	0
Interest income	172	118	334	216
Total Other Income	172	118	336	216
Income Tax Expense	0	0	(3)	0
Net Loss	(5,837)	(9,461)	(13,253)	(19,563)
Currency Translation Adjustment	0	0	0	(11)
Comprehensive Loss	$ (5,837)	$ (9,461)	$ (13,253)	$ (19,574)
Net loss per common share—basic and diluted	$ (0.05)	$ (0.09)	$ (0.12)	$ (0.19)
Weighted average shares used in computing net loss per common share—basic and diluted	113,993,237	106,297,699	112,732,767	105,497,939
Products and Services [Member]
Revenues
Total Revenues	$ 493	$ 946	$ 1,039	$ 1,890
Collaborations and Licenses [Member]
Revenues
Total Revenues	42	260	85	306
Grants [Member]
Revenues
Total Revenues	$ 408	$ 149	$ 508	$ 149

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows From Operating Activities
Net loss	$ (13,253)	$ (19,563)
Adjustments to reconcile net loss to net cash used in operating activities:
(Gain) loss on disposal of fixed assets	(2)	0
Depreciation and amortization	570	647
Stock-based compensation	2,553	4,350
Increase (decrease) in cash resulting from changes in:
Accounts receivable	408	(386)
Grants receivable	(308)	(149)
Inventory	(194)	54
Prepaid expenses and other assets	366	210
Accounts payable	(15)	(694)
Accrued expenses	(1,315)	(1,280)
Deferred revenue	(68)	81
Deferred rent	(88)	(72)
Net cash used in operating activities	(11,346)	(16,802)
Cash Flows From Investing Activities
Purchases of fixed assets	(11)	(56)
Proceeds from disposals of fixed assets	2	0
Purchases of intangible assets	0	(70)
Net cash used in investing activities	(9)	(126)
Cash Flows From Financing Activities
Proceeds from issuance of common stock and exercise of warrants, net	5,129	4,135
Employee taxes paid related to net share settlement of equity awards	(145)	(51)
Proceeds from exercise of stock options	0	825
Net cash provided by financing activities	4,984	4,909
Net decrease in cash, cash equivalents, and restricted cash	(6,371)	(12,019)
Cash, cash equivalents, and restricted cash at beginning of period	43,853	62,878
Cash, cash equivalents, and restricted cash at end of period	37,482	50,859
Reconciliation of cash, cash equivalents, and restricted cash to the condensed consolidated balance sheets
Cash and cash equivalents	37,355	50,732
Restricted cash	127	127
Cash, cash equivalents, and restricted cash at end of period	37,482	50,859
Supplemental Disclosure of Cash Flow Information:
Income taxes paid	$ 3	$ 0

Description of Business	6 Months Ended
Description of Business	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	Note 1. Description of Business Nature of operations Organovo Holdings, Inc., (“Organovo Holdings,” and collectively with its subsidiaries, “the Company”) is a biotechnology company pioneering a unique set of therapeutic and drug profiling capabilities based on its revolutionary ability to 3D bioprint liver tissues that emulate human biology and disease. The Company is developing its in vivo liver tissues to treat a range of life-threatening, orphan diseases, for which there are limited treatment options other than organ transplantation. The Company’s program focused on an orphan disease known as Alpha-1-antitrypsin deficiency (“A1AT”), received the U.S. Food and Drug Administration’s (“FDA”) orphan drug designation in December 2017 and is targeted for an Initial New Drug Application (“IND”) filing in calendar-year 2020. Organovo Holdings is also capitalizing on its foundational ability to characterize highly specialized human cells and to build robust, functional human tissues by creating a range of novel in vitro disease modeling platforms, including a broad set of non-alcoholic fatty liver disease (“NAFLD”) and non-alcoholic steatohepatitis (“NASH”) conditions. Except where specifically noted or the context otherwise requires, references to “Organovo Holdings,” “the Company,” “we,” “our,” and “us” in these notes to the condensed consolidated financial statements refers to Organovo Holdings, Inc. and its wholly owned subsidiaries, Organovo, Inc., Samsara Sciences, Inc., and Organovo U.K., Ltd. In March 2018, the U.K. operations were combined with Organovo, Inc.’s operations.

Summary of Significant Accounting Policies	6 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Basis of presentation and principles of consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not necessarily include all information and notes required by GAAP for complete financial statements. The balance sheet at March 31, 2018 is derived from the Company’s audited balance sheet at that date. The condensed consolidated financial statements include the accounts of Organovo Holdings and its wholly owned subsidiaries. All material intercompany accounts and transactions have been eliminated in consolidation. In the opinion of management, the unaudited financial information for the interim periods presented reflects all adjustments, which are only normal and recurring, necessary for a fair statement of the Company’s financial position, results of operations, stockholders’ equity and cash flows. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended March 31, 2018, as filed with the Securities and Exchange Commission (“SEC”). Operating results for interim periods are not necessarily indicative of operating results for the Company’s fiscal year ending March 31, 2019. Reclassification of prior year presentation As a result of the adoption of the new accounting standard associated with clarifying presentation and classification in the statement of cash flows, certain reclassifications have been made to the prior period financial statements to conform with the current period presentation. These reclassifications did not have any effect on previously reported cash flows, net loss, or financial position. Liquidity As of September 30, 2018, the Company had cash, cash equivalents, and restricted cash of approximately $37.5 million, consisting of cash and cash equivalents of $37.4 million and restricted cash of $0.1 million. The restricted cash was pledged as collateral for two letters of credit the Company is required to maintain as security deposits under the terms of the leases of its facilities. The Company had an accumulated deficit of approximately $247.4 million. The Company also had negative cash flows from operations of approximately $11.3 million during the six months ended September 30, 2018. Through September 30, 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, licenses, and grants. During the six months ended September 30, 2018, the Company issued 3,762,130 shares of its common stock through its ATM facility and received net proceeds of approximately $5.1 million. Based on its current operating plan and available cash resources, the Company has sufficient resources to fund its business for at least the next twelve months from the financial statement issuance date. The Company will need additional capital to further fund the development of its therapeutic tissues focusing on critical unmet medical needs in the liver disease space and to fund the development and commercialization 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. 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, the Company cannot be sure that additional financing will be available when needed or that, if available, financing will be obtained on terms favorable to it or to its stockholders. Having insufficient funds may require the Company to delay, scale back, or eliminate some or all of its development programs or relinquish rights to its technology on less favorable terms than it would otherwise choose. Failure to obtain adequate financing could eventually adversely affect its ability to operate as a going concern. If the Company continues to raise additional funds from the issuance of equity securities, there will be substantial dilution to its existing stockholders. If the Company raises 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 its ability to operate its business. Use of estimates The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect certain reported amounts and disclosures. Actual results could differ from those estimates. Significant estimates used in preparing the condensed consolidated financial statements include those assumed in revenue recognition, the valuation of stock-based compensation expense, and the valuation allowance on deferred tax assets. On an ongoing basis, management reviews these estimates and assumptions. Revenue recognition The Company generates revenues from payments received from research service agreements, product sales, collaborative agreements with partners including pharmaceutical and biotechnology companies and academic institutions, licenses, and grants from the National Institutes of Health (“NIH”) and private not-for-profit organizations. 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 September 30, 2018 and March 31, 2018, the Company had approximately $619,000 and $687,000, respectively, in deferred revenue related to its research service agreements, collaborative agreements, and licenses within the scope of Topic 606. In the six months ended September 30, 2018 the Company recognized revenue on approximately $93,000 that had been recorded as deferred revenue at March 31, 2018. Effective April 1, 2018, the Company adopted the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”), Topic 606, Revenue from Contracts with Customers (“Topic 606”). Under Topic 606, the Company recognizes revenue when (or as) the promised services are transferred to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those services. To determine revenue recognition for arrangements the Company concludes are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) the performance obligation(s) are satisfied. At contract inception, the Company assesses the goods or services promised within each contract, assesses whether each promised good or service is distinct and identifies those that are performance obligations. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Service revenues The Company’s service-based business, Organovo, Inc., utilizes its NovoGen® bioprinting platform to provide customers access to its highly specialized tissues that model human biology and disease, and to in vitro testing services based on that technology. These contracts with customers contain multiple performance obligations including: (i) bioprinting tissues for the customer, (ii) reporting the results of tests performed on the printed tissues pursuant to the agreed upon work plan through exposure of the tissue to various factors (including the customer’s proprietary compound), and (iii) delivering specific byproduct study materials, which are satisfied, respectively, at each of the following points in time: (i) upon completion of manufacturing of the bioprinted tissue for the customer, (ii) upon delivery of the report on tests performed on the tissue, and (iii) upon making certain study materials generated from the aforementioned testing process available to the customer. The customer does not have access or control of any performance obligation prior to the point in time of full completion of the corresponding performance satisfying event as defined above. Furthermore, although the service can be customized for each customer, it is not so highly customized as to not have an alternative use either to other customers or to the Company without significant economic consequences or rework. Accordingly, the Company’s service-based business utilizes point-in-time recognition under Topic 606. For service contracts, the Company allocates the transaction price to each performance obligation based on the estimated relative standalone selling prices of the promised products or services underlying each performance obligation. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. The transaction price for service business contracts is a fixed consideration. Product sales, net The Company’s product-based business, Samsara Sciences, Inc., produces high-quality cell-based products for use in Organovo’s 3D tissue manufacturing and for use by life science customers. The Company recognizes product revenue when the performance obligation is satisfied, which is at the point in time the customer obtains control of the Company’s product, typically upon delivery. Product revenues are recorded at the transaction price, net of any estimates for variable consideration under Topic 606. The Company’s process for estimating variable consideration does not differ materially from its historical practices. Variable consideration is estimated using the expected value method which considers the sum of probability-weighted amounts in a range of possible amounts under the contract. Product revenue reflects the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the individual contracts. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results vary materially from the Company’s estimates, the Company will adjust these estimates, which will affect revenue from product sales and earnings in the period such estimates are adjusted. The Company provides no right of return to its customers except in cases where a customer obtains authorization from the Company for the return. To date, there have been no product returns. The Company will continue to assess its estimates of variable consideration as it accumulates additional historical data and will adjust its estimates accordingly. Collaborative research, development, and licenses The Company enters into collaborative agreements with partners that typically include one or more of the following: (i) non-exclusive license fees; (ii) non-refundable up-front fees; (iii) payments for reimbursement of research costs; (iv) payments associated with achieving specific development milestones; and (v) royalties based on specified percentages of net product sales, if any. At the initiation of an agreement, the Company analyzes whether it results in a contract with a customer under Topic 606 or in an arrangement with a collaborator subject to guidance under ASC 808, Collaborative Arrangements (“Topic 808”). The Company considers a variety of factors in determining the appropriate estimates and assumptions under these arrangements, such as whether the elements are distinct performance obligations, whether there are determinable stand-alone prices, and whether any licenses are functional or symbolic. The Company evaluates each performance obligation to determine if it can be satisfied and recognized as revenue at a point in time or over time. Typically, non-exclusive license fees, non-refundable upfront fees, and funding of research activities are considered fixed, while milestone payments are identified as variable consideration which must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. The Company’s collaborative agreements that were not completed at the implementation of Topic 606 on April 1, 2018, consisted of research collaboration and limited technology access licenses. These agreements provide the licensee with a non-exclusive, non-transferable, limited, royalty-free technology license, including access to Organovo’s proprietary bioprinter platform, training, and continued support by means of consumables and consultation throughout the duration of the contract. The Company has determined the intellectual property license is not distinct from the continued support promised under the agreement and is therefore a single combined performance obligation. The Company recognizes revenue for these combined performance obligations over time for the duration of the license period, as the combined performance obligation will not be fully satisfied until the end of the contract. For the six months ended September 30, 2018, all collaborations and licenses revenue was within the scope of Topic 606 and recognized accordingly. See “Note 4. Collaborative Research, Development, and License Agreements” for more information on the Company’s collaborative agreements. Grant revenue In July 2017, the National Institutes of Health (“NIH”) awarded the Company a “Research and Development” grant totaling approximately $1,657,000 of funding over three years. The Company has concluded this government grant is not within the scope of Topic 606, as government entities do not meet the definition of a “customer” as defined by Topic 606, as there is not considered to be a transfer of control of goods or services to the government entity funding the grant. Additionally, the Company has concluded this government grant does meet the definition of a contribution and is a non-reciprocal transaction, however, Subtopic 958-605, Not-for-Profit-Entities-Revenue Recognition does not apply, as the Company is a business entity and the grant is with a governmental agency. Revenues from this 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 as the Company incurs expenses that are related to the grant. The Company believes this policy is consistent with the overarching premise in Topic 606, to ensure that it recognizes revenues to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services, even though there is no “exchange” as defined in the ASC. The Company believes the recognition of revenue as costs are incurred and amounts become earned/realizable is analogous to the concept of transfer of control of a service over time under ASC 606. Revenue recognized under this grant was approximately $408,000 and $508,000 for the three and six months ended September 30, 2018, respectively. Revenue recognized under this grant was approximately $149,000 for the three and six months ended September 30, 2017. Cost of revenues The Company reported approximately $0.1 million and $0.2 million in cost of revenues for the three and six months ended September 30, 2018, respectively. The Company reported approximately $0.3 million and $0.6 million in cost of revenues for the three and six months ended September 30, 2017, respectively. Cost of revenues consists of costs related to manufacturing and delivering product and service revenue. 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, 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 three and six months ended September 30, 2018 or 2017, as the Company reported a net loss for each respective period and the effect would have been anti-dilutive. Common stock equivalents excluded from computing diluted net loss per share were approximately 17.8 million at September 30, 2018, and 15.4 million at September 30, 2017. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies. Unless otherwise stated, the Company believes that the impact of the recently issued accounting pronouncements that are not yet effective will not have a material impact on its consolidated financial position or results of operations upon adoption. Adoption of New Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (“Topic 606”), which supersedes most existing revenue recognition guidance in U.S. generally accepted accounting principles (“GAAP”), including most industry-specific guidance. The standard 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 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, Revenue from Contracts with Customers, which deferred by one year the effective date for all entities, with application permitted as of the original effective date. The standard allows for either a full retrospective or modified retrospective method of adoption. The Company adopted this standard on its effective date, April 1, 2018, under the modified retrospective method of adoption. Under this method, entities recognize the cumulative impact of applying the new standard at the date of adoption without restatement of prior periods presented. The cumulative effect of applying the new standard to contracts that were not completed as of April 1, 2018 did not have a material impact on the Company’s consolidated financial position, results of operations, or cash flows. The new standard also requires enhanced disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. See “Note 2. Summary of Significant Accounting Policies” for further discussion. Topic 606 supersedes the revenue recognition requirements in ASC Topic 605, Revenue Recognition (“Topic 605”). While results for reporting periods beginning after April 1, 2018 are presented under Topic 606, all prior period amounts are not adjusted and continue to be reported under the accounting standards in effect during these prior periods. The accounting policies for revenue recognition for periods prior to April 1, 2018 are described in “Note 1. Description of Business and Summary of Significant Accounting Policies” of the Notes to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended March 31, 2018. Adoption of this ASC did not have a material impact on the Company’s condensed consolidated financial statements. Refer to the revenue recognition disclosure above. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The standard clarifies the presentation of restricted cash and cash equivalents and requires companies to include restricted cash and cash equivalents in the beginning and ending balances of cash and cash equivalents on the statement of cash flows. The standard also requires additional disclosures to describe the amount and detail of the restriction by balance sheet line item. The new standard was effective for the Company on April 1, 2018. The Company adopted this standard using the retrospective transition method by restating its condensed consolidated statements of cash flows to include restricted cash of $0.1 million in the beginning and ending cash, cash equivalents, and restricted cash balance. Net cash flows for the six months ended September 30, 2017, did not change as a result of including restricted cash with cash and cash equivalents when reconciling the beginning-of-period and end-of-period amounts presented on the statements of cash flows. In May 2017, the FASB issued ASU No. 2017-09, Compensation - Stock Compensation (Topic 718): 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. The new standard was effective for annual reporting periods beginning after April 1, 2018, and interim periods within those annual reporting periods. The adoption of this guidance had no impact on the Company’s financial statements. In December 2017, the United States (“U.S.”) enacted the Tax Cuts and Jobs Act (the “2017 Act”), which changes existing U.S. tax law and includes various provisions that are expected to affect public companies. The 2017 Act (i) changes U.S. corporate tax rates, (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 2017 Act will also impact estimates of a company’s deferred tax assets and liabilities. The Company is currently in the early stages of evaluating the financial statement impact of the 2017 Act. Based on initial assessments, the Company expects significant adjustments to its gross deferred tax assets and liabilities; however, it also expects to record a corresponding offset to its estimated full valuation allowance against its net deferred tax assets, which should result in minimal net effect to its provision for income taxes. In accordance with SEC issued guidance under Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”), the Company anticipates a minimal impact to its financial statements. Recent Accounting Pronouncements Not Yet Adopted 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 the Company 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 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 the Company’s financial statements as the Company’s only derivative liabilities were all exercised or expired as of March 31, 2017. In February 2018, the FASB issued ASU No. 2018-02, Income Statement – Reporting Comprehensive Income (“Topic 220”), which allows stranded tax effects resulting from the Tax Cuts and Jobs Act to be reclassified from accumulated other comprehensive income to retained earnings. The amendment only relates to the reclassification of the income tax effects of the Tax Cuts and Jobs Act; thus, the underlying guidance relating to the effect of a change in tax laws be included in income from continuing operations is not affected. The amendments in Topic 220 are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. This new guidance is effective for the Company on April 1, 2019. The requirements of ASU 2018-02 are not expected to have a significant impact on the Company’s financial statements.

Stockholders' Equity

6 Months Ended

Sep. 30, 2018

Equity [Abstract]

Stockholders' Equity

Note 3. Stockholders’ Equity

Stock-based compensation expense and valuation information

Stock-based awards include (i) stock options and (ii) restricted stock units under the 2012 Equity Incentive Plan (“2012 Plan”), (iii) performance-based restricted stock units under an Incentive Award Performance-Based Restricted Stock Unit Agreement, and (iv) rights to purchase stock under the 2016 Employee Stock Purchase Plan (“ESPP”). The Company calculates the grant date fair value of all stock-based awards in determining the stock-based compensation expense.

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

	Three Months Ended		Three Months Ended		Six Months Ended		Six Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Research and development	$	229	$	384	$	431	$	715
General and administrative	$	1,045	$	1,914	$	2,122	$	3,635
Total	$	1,274	$	2,298	$	2,553	$	4,350

The total unrecognized compensation cost related to unvested stock option grants as of September 30, 2018 was approximately $10,231,536 and the weighted average period over which these grants are expected to vest is 3.14 years.

The total unrecognized compensation cost related to unvested restricted stock units (not including performance-based restricted stock units) as of September 30, 2018 was approximately $4,585,160, which will be recognized over a weighted average period of 2.82 years.

The total unrecognized compensation cost related to unvested performance-based restricted stock units as of September 30, 2018 was approximately $166,075, which will be recognized over a weighted average period of 1.98 years.

The total unrecognized stock-based compensation cost related to unvested employee stock purchase plan shares as of September 30, 2018 was approximately $14,000, which will be recognized over a period of 5 months.

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 weighted average assumptions:

	Three Months Ended			Three Months Ended			Six Months Ended			Six Months Ended
	September 30, 2018			September 30, 2017			September 30, 2018			September 30, 2017
Dividend yield		—			—			—			—
Volatility		73.19	%		70.97	%		72.98	%		76.58	%
Risk-free interest rate		2.74	%		1.78	%		2.75	%		1.81	%
Expected life of options	6.00 years			6.00 years			6.00 years			6.00 years
Weighted average grant date fair value	$	0.73		$	1.25		$	0.84		$	1.73

The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. Considering the expected life of these options, the Company determined that a blend of historical volatility and implied volatility of comparable companies whose share prices are publicly available is more reflective of market conditions and a better indicator of expected volatility than using purely Company-specific historical volatility. The risk-free interest rate assumption was based on 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 and performance-based 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 assumptions:

	Three Months Ended		Three Months Ended		Six Months Ended		Six Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Dividend yield		—		—		—		—
Volatility	61.35 - 80.23%		43.03 - 74.70%		61.35 - 80.23%		43.03 - 74.70%
Risk-free interest rate	1.85 - 2.29%		0.79 - 1.10%		1.85 - 2.29%		0.79 - 1.10%
Expected term	6 months		6 months		6 months		6 months
Grant date fair value	$0.30 - $0.45		$0.52 - $1.04		$0.30 - $0.45		$0.52 - $1.04

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, the Company determined that a blend of historical volatility and implied volatility of comparable companies whose share prices are publicly available was more reflective of market conditions and a better indicator of expected volatility than using purely Company-specific historical volatility. As of September 1, 2017 and the beginning of the second year of ESPP offering periods, the Company is using the Company-specific historical volatility rate as the 6-month historical volatility is now a better indicator of expected volatility. 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 current plans to issue shares of preferred stock.

Common stock

In December 2014, the Company entered into an equity offering sales agreement (the “2014 Sales Agreement”) with an investment banking firm. In July 2016, the Company registered the sale of up to $26.6 million of common stock under the 2014 Sales Agreement pursuant to its shelf registration statement on Form S-3 (File No. 333-202382) filed with the SEC on February 27, 2015 (the “2015 Shelf”) that expired on March 17, 2018. Prior to its expiration, the Company 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.

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.

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 issued pursuant to the Company’s 2018 Shelf.

On July 26, 2018, the Company filed an amendment to its certificate of incorporation to increase the number of authorized shares of common stock to 200,000,000 shares.

During the three and six months ended September 30, 2018, the Company issued 1,676,590 and 3,762,130 shares of common stock, respectively, for net proceeds of $2.1 million and $5.1 million, respectively, in at-the-market offerings under the 2018 Sales Agreement. During the three and six months ended September 30, 2017, the Company issued 398,728 and 1,538,217 shares of common stock, respectively, for net proceeds of $1.0 million and $4.0 million, respectively, under the 2014 Sales Agreement.

As of September 30, 2018, the Company has sold an aggregate of 3,762,130 shares of common stock in at-the-market offerings under the 2018 Sales Agreement, with net proceeds of approximately $5.1 million. Based on these sales, the Company cannot raise more than an aggregate of $94.8 million in future offerings under the 2018 Shelf, including the $44.8 million remaining available 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.

Restricted stock units

On August 15, 2018 in connection with the appointment of a new Chief Medical Officer (“CMO”), the Company allocated 160,714 Restricted Stock Units (“RSUs”) outside of the 2012 Plan. The Company intends for these to be “inducement awards” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While outside the Company’s 2012 Plan, the terms and conditions of these awards are consistent with awards granted to the Company’s executive officers pursuant to the 2012 Plan.

A summary of the Company’s restricted stock unit (not including performance-based restricted stock units) activity from March 31, 2018 through September 30, 2018 is as follows:

	Number of Shares			Weighted Average Price
Unvested at March 31, 2018		2,035,345		$	2.89
Granted		1,759,520		$	1.18
Vested		(412,368	)	$	2.63
Cancelled / forfeited		(772,732	)	$	2.38
Unvested at September 30, 2018		2,609,765		$	1.94

Performance-based restricted stock units

On April 24, 2017, in connection with the appointment of a new Chief Executive Officer (“CEO”), the Company allocated 208,822 Performance-Based Restricted Stock Units (“PBRSUs”) outside of the 2012 Plan. The Company intends for these to be “inducement awards” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While outside the Company’s 2012 Plan, the terms and conditions of these awards are generally 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 PBRSUs allocated by the Company on April 24, 2017. The units are 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 September 30, 2018, 100% of the Negative Adjusted EBITDA tranche had vested and the additional 20% overachievement is expected to vest in a future year. As of September 30, 2018, no other tranches are currently expected to vest in fiscal year 2019.

The grant date fair values 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.

A summary of the Company’s performance-based restricted stock unit activity from March 31, 2018 through September 30, 2018 is as follows:

	Number of Shares			Maximum Number of Shares Eligible to be Issued			Weighted Average Price
Unvested at March 31, 2018		167,058			200,470		$	1.88
Granted		—			—		$	—
Vested		(41,764	)		(41,764	)	$	1.88
Cancelled / forfeited		—			—		$	—
Unvested at September 30, 2018		125,294			158,706		$	1.88

Stock options

On April 24, 2017, in connection with the appointment of a new CEO, the Company granted 2,088,212 stock options outside of the 2012 Plan. The Company intends for these to be “inducement awards” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While granted outside the Company’s 2012 Plan, the terms and conditions of these awards are consistent with awards granted to the Company’s executive officers pursuant to the 2012 Plan. On August 15, 2018 in connection with the appointment of a new CMO, the Company allocated 974,694 stock options outside of the 2012 Plan. The Company intends for these to be “inducement awards” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While outside the Company’s 2012 Plan, the terms and conditions of these awards are consistent with awards granted to the Company’s executive officers pursuant to the 2012 Plan. These stock options vest over a four-year period, with a quarter of the option shares vesting on the one-year anniversary of the vesting commencement date and the remaining options shares vesting in equal quarterly installments over the next 12 quarterly periods.

A summary of the Company’s stock option activity from March 31, 2018 to September 30, 2018 is as follows:

	Options Outstanding			Weighted Average Exercise Price		Aggregate Intrinsic Value
Outstanding at March 31, 2018		10,132,312		$	4.01	$	591,082
Options granted		7,947,694		$	1.29	$	—
Options cancelled / forfeited		(3,246,759	)	$	5.12	$	—
Options exercised		—		$	—	$	—
Outstanding at September 30, 2018		14,833,247		$	2.31	$	769,236
Vested and Exercisable at September 30, 2018		4,904,840		$	3.66	$	665,745

The weighted average remaining contractual term of options exercisable and outstanding at September 30, 2018 was approximately 6.05 years.

Employee Stock Purchase Plan

The Company reserved 1,500,000 shares of common stock for issuance under the ESPP. 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 the lower of $25,000 per employee per year or 10,000 shares per employee per six-month 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. At September 30, 2018, there were 1,230,735 shares available for purchase under the ESPP.

Warrants

The following table summarizes warrant activity for the six months ended September 30, 2018:

	Warrants		Weighted Average Exercise Price
Balance at March 31, 2018		220,000	$	7.19
Granted		—	$	—
Exercised		—	$	—
Cancelled		—	$	—
Balance at September 30, 2018		220,000	$	7.19

The warrants outstanding at September 30, 2018 are exercisable at prices between $6.84 and $7.62 per share and have a weighted average remaining term of approximately 0.71 years.

Common stock reserved for future issuance

Common stock reserved for future issuance consisted of the following at September 30, 2018:

Common stock warrants outstanding			220,000
Common stock options outstanding under the 2008 Plan			622,192
Common stock options outstanding and reserved under the 2012 Plan			11,148,149
Common stock reserved under the 2012 Plan			11,042,706
Common stock reserved under the 2016 Employee Stock Purchase Plan			1,230,735
Restricted stock units outstanding under the 2012 Plan			2,449,051
Common stock options outstanding and reserved under the Incentive Award Agreement			3,062,906
Restricted stock units outstanding under the Incentive Award Agreement			160,714
Performance-based restricted stock units outstanding under the Incentive Award Agreement			158,706
Total at September 30, 2018			30,095,159

Collaborative Research, Development, and License Agreements	6 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborative Research, Development, and License Agreements	Note 4. Collaborative Research, Development, and License Agreements In April 2015, the Company entered into a research collaboration agreement with a third party to develop custom tissue models for fixed fees. No revenue was recorded under this agreement during the three and six months ended September 30, 2018. Collaboration revenue of $150,000 was recorded for the three and six months ended September 30, 2017. The Company completed its obligations under this agreement in September 2017. 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. No revenue was recorded under this agreement during the three and six months ended September 30, 2018 and 2017. In June 2016, the Company entered into a collaborative non-exclusive 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 was initially recorded as deferred revenue. No revenue was recorded under this agreement during the three and six months ended September 30, 2018. Revenue of $18,000 and $35,000 was recorded under this agreement during the three and six months ended September 30, 2017, respectively. The Company does not anticipate recording any further revenue under this agreement. In December 2016, the Company signed another collaborative non-exclusive 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 2017, which were initially recorded as deferred revenue. Revenue of $10,000 and $19,000 was recorded under this agreement for the three and six months ended September 30, 2018, respectively. Revenue of $9,000 and $19,000 has been recorded under this agreement for the three and six months ended September 30, 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 non-refundable 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 was initially recorded as deferred revenue. Revenue of approximately $14,000 and $29,000 has been recorded under this agreement for the three and six months ended September 30, 2018, respectively. Revenue of approximately $14,000 has been recorded under this agreement for the three and six months ended September 30, 2017, beginning subsequent to the installation of the printer in July 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 the two years for the license to the 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 and the second annual payment of $75,000 in April 2018, which were initially recorded as deferred revenue. Revenue of $19,000 and $38,000 has been recorded under this agreement for the three and six months ended September 30, 2018, respectively. Revenue of $18,750 and $37,500 was recorded under this agreement for the three and six months ended September 30, 2017, respectively. 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 recorded no revenue under this agreement for the three and six months ended September 30, 2018. The Company recorded $50,000 for the three and six months ended September 30, 2017.

Commitments and Contingencies

6 Months Ended

Sep. 30, 2018

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 5. Commitments and Contingencies

Operating leases

Since July 2012, the Company has leased its main facilities at 6275 Nancy Ridge Drive, San Diego, California 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 for 14,685 of the total rentable square footage was amended to accelerate the expiration date from December 15, 2018 to October 31, 2018 . The remainder of the total rentable square footage under the lease expires on September 1, 2021, unless the Company exercises its option to terminate the lease on or after September 1, 2019 with 9 months prior written notice.

The Company also previously leased a second facility from February 1, 2015 through January 31, 2018, consisting of 5,803 rentable square feet of office and lab space located at 6310 Nancy Ridge Drive, San Diego, California 92121, with a monthly rent of approximately $12,000 commencing on April 1, 2015, which increased be 3% each 12-month anniversary of the 36 month lease.

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 $326,000 and $651,000 for the three and six months ended September 30, 2018, respectively, and $365,000 and $731,000 for the three and six months ended September 30, 2017, 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 September 30, 2018, are as follows (in thousands):

Fiscal year ended March 31, 2019	$	565,411
Fiscal year ended March 31, 2020		1,073,027
Fiscal year ended March 31, 2021		1,104,070
Fiscal year ended March 31, 2022		467,594
Fiscal year ended March 31, 2023		—
Thereafter		—
Total	$	3,210,102

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.

Concentrations	6 Months Ended
Concentrations	Sep. 30, 2018
Risks And Uncertainties [Abstract]
Concentrations	Note 6. Concentrations Credit risk 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. 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 September 30, 2018.

Related Parties	6 Months Ended
Related Parties	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Parties	Note 7. Related Parties From time to time, the Company will enter into an agreement with a related party 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. These agreements are 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 Therapeutics, Inc. (“Cirius”), 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 in the amount of $255,000 to date, of which $52,000 and $94,000 was recognized as revenue in the three and six months ended September 30, 2018, respectively. The Company has provided ExVive™ Liver Tissue Services for Cirius in the amount of $50,000 in the three and six months ended September 30, 2017. The agreement contains an additional $27,000 of ExVive™ Liver Tissue Services to be completed in the third quarter of Fiscal 2019. During the fiscal year, the Company sold study materials and products to Viscient Biosciences (“Viscient”), an entity which Keith Murphy, a former director and Chief Executive Officer of the Company, serves as Chief Executive Officer. Viscient purchased study materials from Organovo in the amount of $2,000 to date, pursuant to the terms of a Quote which was entered into on September 11, 2018, of which $2,000 was recognized as revenue in the three and six months ended September 30, 2018. Viscient also purchased primary human cell-based products from our subsidiary, Samsara, in the amount of $3,000 to date, pursuant to the terms of multiple Quotes entered into throughout the fiscal year, of which $1,000 and $3,000 was recognized as revenue in the three and six months ended September 30, 2018, respectively. There were no sales to Viscient during the three and six months ended September 30, 2017. Subsequent to September 30, 2018, Viscient executed a Quote to purchase an RNAseq data set and primary human cell-based products from Samsara in the amount of $130,000 which will be recognized in the third quarter of Fiscal 2019.

Subsequent Events	6 Months Ended
Subsequent Events	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Note 8. Subsequent Events Between October 1, 2018 and the date of filing, the Company issued 741,298 shares of its common stock pursuant to its at-the-market (“ATM”) facility for net proceeds of approximately $0.8 million.

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of presentation and principles of consolidation	Basis of presentation and principles of consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not necessarily include all information and notes required by GAAP for complete financial statements. The balance sheet at March 31, 2018 is derived from the Company’s audited balance sheet at that date. The condensed consolidated financial statements include the accounts of Organovo Holdings and its wholly owned subsidiaries. All material intercompany accounts and transactions have been eliminated in consolidation. In the opinion of management, the unaudited financial information for the interim periods presented reflects all adjustments, which are only normal and recurring, necessary for a fair statement of the Company’s financial position, results of operations, stockholders’ equity and cash flows. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended March 31, 2018, as filed with the Securities and Exchange Commission (“SEC”). Operating results for interim periods are not necessarily indicative of operating results for the Company’s fiscal year ending March 31, 2019.
Reclassification of prior year presentation	Reclassification of prior year presentation As a result of the adoption of the new accounting standard associated with clarifying presentation and classification in the statement of cash flows, certain reclassifications have been made to the prior period financial statements to conform with the current period presentation. These reclassifications did not have any effect on previously reported cash flows, net loss, or financial position.
Liquidity	Liquidity As of September 30, 2018, the Company had cash, cash equivalents, and restricted cash of approximately $37.5 million, consisting of cash and cash equivalents of $37.4 million and restricted cash of $0.1 million. The restricted cash was pledged as collateral for two letters of credit the Company is required to maintain as security deposits under the terms of the leases of its facilities. The Company had an accumulated deficit of approximately $247.4 million. The Company also had negative cash flows from operations of approximately $11.3 million during the six months ended September 30, 2018. Through September 30, 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, licenses, and grants. During the six months ended September 30, 2018, the Company issued 3,762,130 shares of its common stock through its ATM facility and received net proceeds of approximately $5.1 million. Based on its current operating plan and available cash resources, the Company has sufficient resources to fund its business for at least the next twelve months from the financial statement issuance date. The Company will need additional capital to further fund the development of its therapeutic tissues focusing on critical unmet medical needs in the liver disease space and to fund the development and commercialization 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. 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, the Company cannot be sure that additional financing will be available when needed or that, if available, financing will be obtained on terms favorable to it or to its stockholders. Having insufficient funds may require the Company to delay, scale back, or eliminate some or all of its development programs or relinquish rights to its technology on less favorable terms than it would otherwise choose. Failure to obtain adequate financing could eventually adversely affect its ability to operate as a going concern. If the Company continues to raise additional funds from the issuance of equity securities, there will be substantial dilution to its existing stockholders. If the Company raises 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 its ability to operate its business.
Use of estimates	Use of estimates The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect certain reported amounts and disclosures. Actual results could differ from those estimates. Significant estimates used in preparing the condensed consolidated financial statements include those assumed in revenue recognition, the valuation of stock-based compensation expense, and the valuation allowance on deferred tax assets. On an ongoing basis, management reviews these estimates and assumptions.
Revenue recognition	Revenue recognition The Company generates revenues from payments received from research service agreements, product sales, collaborative agreements with partners including pharmaceutical and biotechnology companies and academic institutions, licenses, and grants from the National Institutes of Health (“NIH”) and private not-for-profit organizations. 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 September 30, 2018 and March 31, 2018, the Company had approximately $619,000 and $687,000, respectively, in deferred revenue related to its research service agreements, collaborative agreements, and licenses within the scope of Topic 606. In the six months ended September 30, 2018 the Company recognized revenue on approximately $93,000 that had been recorded as deferred revenue at March 31, 2018. Effective April 1, 2018, the Company adopted the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”), Topic 606, Revenue from Contracts with Customers (“Topic 606”). Under Topic 606, the Company recognizes revenue when (or as) the promised services are transferred to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those services. To determine revenue recognition for arrangements the Company concludes are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) the performance obligation(s) are satisfied. At contract inception, the Company assesses the goods or services promised within each contract, assesses whether each promised good or service is distinct and identifies those that are performance obligations. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Service revenues The Company’s service-based business, Organovo, Inc., utilizes its NovoGen® bioprinting platform to provide customers access to its highly specialized tissues that model human biology and disease, and to in vitro testing services based on that technology. These contracts with customers contain multiple performance obligations including: (i) bioprinting tissues for the customer, (ii) reporting the results of tests performed on the printed tissues pursuant to the agreed upon work plan through exposure of the tissue to various factors (including the customer’s proprietary compound), and (iii) delivering specific byproduct study materials, which are satisfied, respectively, at each of the following points in time: (i) upon completion of manufacturing of the bioprinted tissue for the customer, (ii) upon delivery of the report on tests performed on the tissue, and (iii) upon making certain study materials generated from the aforementioned testing process available to the customer. The customer does not have access or control of any performance obligation prior to the point in time of full completion of the corresponding performance satisfying event as defined above. Furthermore, although the service can be customized for each customer, it is not so highly customized as to not have an alternative use either to other customers or to the Company without significant economic consequences or rework. Accordingly, the Company’s service-based business utilizes point-in-time recognition under Topic 606. For service contracts, the Company allocates the transaction price to each performance obligation based on the estimated relative standalone selling prices of the promised products or services underlying each performance obligation. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. The transaction price for service business contracts is a fixed consideration. Product sales, net The Company’s product-based business, Samsara Sciences, Inc., produces high-quality cell-based products for use in Organovo’s 3D tissue manufacturing and for use by life science customers. The Company recognizes product revenue when the performance obligation is satisfied, which is at the point in time the customer obtains control of the Company’s product, typically upon delivery. Product revenues are recorded at the transaction price, net of any estimates for variable consideration under Topic 606. The Company’s process for estimating variable consideration does not differ materially from its historical practices. Variable consideration is estimated using the expected value method which considers the sum of probability-weighted amounts in a range of possible amounts under the contract. Product revenue reflects the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the individual contracts. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results vary materially from the Company’s estimates, the Company will adjust these estimates, which will affect revenue from product sales and earnings in the period such estimates are adjusted. The Company provides no right of return to its customers except in cases where a customer obtains authorization from the Company for the return. To date, there have been no product returns. The Company will continue to assess its estimates of variable consideration as it accumulates additional historical data and will adjust its estimates accordingly. Collaborative research, development, and licenses The Company enters into collaborative agreements with partners that typically include one or more of the following: (i) non-exclusive license fees; (ii) non-refundable up-front fees; (iii) payments for reimbursement of research costs; (iv) payments associated with achieving specific development milestones; and (v) royalties based on specified percentages of net product sales, if any. At the initiation of an agreement, the Company analyzes whether it results in a contract with a customer under Topic 606 or in an arrangement with a collaborator subject to guidance under ASC 808, Collaborative Arrangements (“Topic 808”). The Company considers a variety of factors in determining the appropriate estimates and assumptions under these arrangements, such as whether the elements are distinct performance obligations, whether there are determinable stand-alone prices, and whether any licenses are functional or symbolic. The Company evaluates each performance obligation to determine if it can be satisfied and recognized as revenue at a point in time or over time. Typically, non-exclusive license fees, non-refundable upfront fees, and funding of research activities are considered fixed, while milestone payments are identified as variable consideration which must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. The Company’s collaborative agreements that were not completed at the implementation of Topic 606 on April 1, 2018, consisted of research collaboration and limited technology access licenses. These agreements provide the licensee with a non-exclusive, non-transferable, limited, royalty-free technology license, including access to Organovo’s proprietary bioprinter platform, training, and continued support by means of consumables and consultation throughout the duration of the contract. The Company has determined the intellectual property license is not distinct from the continued support promised under the agreement and is therefore a single combined performance obligation. The Company recognizes revenue for these combined performance obligations over time for the duration of the license period, as the combined performance obligation will not be fully satisfied until the end of the contract. For the six months ended September 30, 2018, all collaborations and licenses revenue was within the scope of Topic 606 and recognized accordingly. See “Note 4. Collaborative Research, Development, and License Agreements” for more information on the Company’s collaborative agreements. Grant revenue In July 2017, the National Institutes of Health (“NIH”) awarded the Company a “Research and Development” grant totaling approximately $1,657,000 of funding over three years. The Company has concluded this government grant is not within the scope of Topic 606, as government entities do not meet the definition of a “customer” as defined by Topic 606, as there is not considered to be a transfer of control of goods or services to the government entity funding the grant. Additionally, the Company has concluded this government grant does meet the definition of a contribution and is a non-reciprocal transaction, however, Subtopic 958-605, Not-for-Profit-Entities-Revenue Recognition does not apply, as the Company is a business entity and the grant is with a governmental agency. Revenues from this 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 as the Company incurs expenses that are related to the grant. The Company believes this policy is consistent with the overarching premise in Topic 606, to ensure that it recognizes revenues to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services, even though there is no “exchange” as defined in the ASC. The Company believes the recognition of revenue as costs are incurred and amounts become earned/realizable is analogous to the concept of transfer of control of a service over time under ASC 606. Revenue recognized under this grant was approximately $408,000 and $508,000 for the three and six months ended September 30, 2018, respectively. Revenue recognized under this grant was approximately $149,000 for the three and six months ended September 30, 2017.
Cost of revenues	Cost of revenues The Company reported approximately $0.1 million and $0.2 million in cost of revenues for the three and six months ended September 30, 2018, respectively. The Company reported approximately $0.3 million and $0.6 million in cost of revenues for the three and six months ended September 30, 2017, respectively. Cost of revenues consists of costs related to manufacturing and delivering product and service revenue.
Net loss per share	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, 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 three and six months ended September 30, 2018 or 2017, as the Company reported a net loss for each respective period and the effect would have been anti-dilutive. Common stock equivalents excluded from computing diluted net loss per share were approximately 17.8 million at September 30, 2018, and 15.4 million at September 30, 2017.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies. Unless otherwise stated, the Company believes that the impact of the recently issued accounting pronouncements that are not yet effective will not have a material impact on its consolidated financial position or results of operations upon adoption. Adoption of New Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (“Topic 606”), which supersedes most existing revenue recognition guidance in U.S. generally accepted accounting principles (“GAAP”), including most industry-specific guidance. The standard 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 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, Revenue from Contracts with Customers, which deferred by one year the effective date for all entities, with application permitted as of the original effective date. The standard allows for either a full retrospective or modified retrospective method of adoption. The Company adopted this standard on its effective date, April 1, 2018, under the modified retrospective method of adoption. Under this method, entities recognize the cumulative impact of applying the new standard at the date of adoption without restatement of prior periods presented. The cumulative effect of applying the new standard to contracts that were not completed as of April 1, 2018 did not have a material impact on the Company’s consolidated financial position, results of operations, or cash flows. The new standard also requires enhanced disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. See “Note 2. Summary of Significant Accounting Policies” for further discussion. Topic 606 supersedes the revenue recognition requirements in ASC Topic 605, Revenue Recognition (“Topic 605”). While results for reporting periods beginning after April 1, 2018 are presented under Topic 606, all prior period amounts are not adjusted and continue to be reported under the accounting standards in effect during these prior periods. The accounting policies for revenue recognition for periods prior to April 1, 2018 are described in “Note 1. Description of Business and Summary of Significant Accounting Policies” of the Notes to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended March 31, 2018. Adoption of this ASC did not have a material impact on the Company’s condensed consolidated financial statements. Refer to the revenue recognition disclosure above. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The standard clarifies the presentation of restricted cash and cash equivalents and requires companies to include restricted cash and cash equivalents in the beginning and ending balances of cash and cash equivalents on the statement of cash flows. The standard also requires additional disclosures to describe the amount and detail of the restriction by balance sheet line item. The new standard was effective for the Company on April 1, 2018. The Company adopted this standard using the retrospective transition method by restating its condensed consolidated statements of cash flows to include restricted cash of $0.1 million in the beginning and ending cash, cash equivalents, and restricted cash balance. Net cash flows for the six months ended September 30, 2017, did not change as a result of including restricted cash with cash and cash equivalents when reconciling the beginning-of-period and end-of-period amounts presented on the statements of cash flows. In May 2017, the FASB issued ASU No. 2017-09, Compensation - Stock Compensation (Topic 718): 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. The new standard was effective for annual reporting periods beginning after April 1, 2018, and interim periods within those annual reporting periods. The adoption of this guidance had no impact on the Company’s financial statements. In December 2017, the United States (“U.S.”) enacted the Tax Cuts and Jobs Act (the “2017 Act”), which changes existing U.S. tax law and includes various provisions that are expected to affect public companies. The 2017 Act (i) changes U.S. corporate tax rates, (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 2017 Act will also impact estimates of a company’s deferred tax assets and liabilities. The Company is currently in the early stages of evaluating the financial statement impact of the 2017 Act. Based on initial assessments, the Company expects significant adjustments to its gross deferred tax assets and liabilities; however, it also expects to record a corresponding offset to its estimated full valuation allowance against its net deferred tax assets, which should result in minimal net effect to its provision for income taxes. In accordance with SEC issued guidance under Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”), the Company anticipates a minimal impact to its financial statements. Recent Accounting Pronouncements Not Yet Adopted 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 the Company 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 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 the Company’s financial statements as the Company’s only derivative liabilities were all exercised or expired as of March 31, 2017. In February 2018, the FASB issued ASU No. 2018-02, Income Statement – Reporting Comprehensive Income (“Topic 220”), which allows stranded tax effects resulting from the Tax Cuts and Jobs Act to be reclassified from accumulated other comprehensive income to retained earnings. The amendment only relates to the reclassification of the income tax effects of the Tax Cuts and Jobs Act; thus, the underlying guidance relating to the effect of a change in tax laws be included in income from continuing operations is not affected. The amendments in Topic 220 are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. This new guidance is effective for the Company on April 1, 2019. The requirements of ASU 2018-02 are not expected to have a significant impact on the Company’s financial statements.

Stockholders' Equity (Tables)

6 Months Ended

Sep. 30, 2018

Class Of Stock [Line Items]

Schedule of Stock-based Compensation Expense

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

	Three Months Ended		Three Months Ended		Six Months Ended		Six Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Research and development	$	229	$	384	$	431	$	715
General and administrative	$	1,045	$	1,914	$	2,122	$	3,635
Total	$	1,274	$	2,298	$	2,553	$	4,350

Fair Value of Employee Stock Options

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

	Three Months Ended			Three Months Ended			Six Months Ended			Six Months Ended
	September 30, 2018			September 30, 2017			September 30, 2018			September 30, 2017
Dividend yield		—			—			—			—
Volatility		73.19	%		70.97	%		72.98	%		76.58	%
Risk-free interest rate		2.74	%		1.78	%		2.75	%		1.81	%
Expected life of options	6.00 years			6.00 years			6.00 years			6.00 years
Weighted average grant date fair value	$	0.73		$	1.25		$	0.84		$	1.73

Fair Value of Employee Stock Purchase Plan

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

	Three Months Ended		Three Months Ended		Six Months Ended		Six Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Dividend yield		—		—		—		—
Volatility	61.35 - 80.23%		43.03 - 74.70%		61.35 - 80.23%		43.03 - 74.70%
Risk-free interest rate	1.85 - 2.29%		0.79 - 1.10%		1.85 - 2.29%		0.79 - 1.10%
Expected term	6 months		6 months		6 months		6 months
Grant date fair value	$0.30 - $0.45		$0.52 - $1.04		$0.30 - $0.45		$0.52 - $1.04

Summary of Stock Option Activity

A summary of the Company’s stock option activity from March 31, 2018 to September 30, 2018 is as follows:

	Options Outstanding			Weighted Average Exercise Price		Aggregate Intrinsic Value
Outstanding at March 31, 2018		10,132,312		$	4.01	$	591,082
Options granted		7,947,694		$	1.29	$	—
Options cancelled / forfeited		(3,246,759	)	$	5.12	$	—
Options exercised		—		$	—	$	—
Outstanding at September 30, 2018		14,833,247		$	2.31	$	769,236
Vested and Exercisable at September 30, 2018		4,904,840		$	3.66	$	665,745

Summary of Warrant Activity

The following table summarizes warrant activity for the six months ended September 30, 2018:

	Warrants		Weighted Average Exercise Price
Balance at March 31, 2018		220,000	$	7.19
Granted		—	$	—
Exercised		—	$	—
Cancelled		—	$	—
Balance at September 30, 2018		220,000	$	7.19

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consisted of the following at September 30, 2018:

Common stock warrants outstanding			220,000
Common stock options outstanding under the 2008 Plan			622,192
Common stock options outstanding and reserved under the 2012 Plan			11,148,149
Common stock reserved under the 2012 Plan			11,042,706
Common stock reserved under the 2016 Employee Stock Purchase Plan			1,230,735
Restricted stock units outstanding under the 2012 Plan			2,449,051
Common stock options outstanding and reserved under the Incentive Award Agreement			3,062,906
Restricted stock units outstanding under the Incentive Award Agreement			160,714
Performance-based restricted stock units outstanding under the Incentive Award Agreement			158,706
Total at September 30, 2018			30,095,159

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 (not including performance-based restricted stock units) activity from March 31, 2018 through September 30, 2018 is as follows:

	Number of Shares			Weighted Average Price
Unvested at March 31, 2018		2,035,345		$	2.89
Granted		1,759,520		$	1.18
Vested		(412,368	)	$	2.63
Cancelled / forfeited		(772,732	)	$	2.38
Unvested at September 30, 2018		2,609,765		$	1.94

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, 2018 through September 30, 2018 is as follows:

	Number of Shares			Maximum Number of Shares Eligible to be Issued			Weighted Average Price
Unvested at March 31, 2018		167,058			200,470		$	1.88
Granted		—			—		$	—
Vested		(41,764	)		(41,764	)	$	1.88
Cancelled / forfeited		—			—		$	—
Unvested at September 30, 2018		125,294			158,706		$	1.88

Commitments and Contingencies (Tables)

6 Months Ended

Sep. 30, 2018

Commitments And Contingencies Disclosure [Abstract]

Future Minimum Annual Operating Lease Payments

Future minimum rental payments required under operating leases that have initial or remaining non-cancelable lease terms in excess of one year as of September 30, 2018, are as follows (in thousands):

Fiscal year ended March 31, 2019	$	565,411
Fiscal year ended March 31, 2020		1,073,027
Fiscal year ended March 31, 2021		1,104,070
Fiscal year ended March 31, 2022		467,594
Fiscal year ended March 31, 2023		—
Thereafter		—
Total	$	3,210,102

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018	Mar. 31, 2017	Nov. 01, 2016
Summary Of Significant Accounting Policies [Line Items]
Cash, cash equivalents, and restricted cash		$ 37,482,000	$ 50,859,000	$ 37,482,000	$ 50,859,000	$ 43,853,000	$ 62,878,000
Cash and cash equivalents		37,355,000	50,732,000	37,355,000	50,732,000	43,726,000
Restricted cash		127,000	127,000	127,000	127,000	127,000
Accumulated deficit		$ (247,373,000)		(247,373,000)		$ (234,120,000)
Cash flow from operations				$ 11,346,000	16,802,000
Issuance of common stock		115,200,421		115,200,421		111,032,957
Deferred revenue		$ 619,000		$ 619,000		$ 668,000
Revenue recognized				93,000
Revenue recognized under grants		943,000	1,355,000	1,632,000	2,345,000
Cost of revenues		100,000	300,000	200,000	600,000
Dilutive effect		0	0	$ 0	$ 0
Common stock equivalents excluded from computing diluted net loss per share				17,800,000	15,400,000
Accounting Standards Update 2016-18 [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash								$ 100,000
NIH Research Grants Two [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized under grants	$ 1,657,000
Grant revenue funding period	3 years
Product [Member]
Summary Of Significant Accounting Policies [Line Items]
Product return revenue				$ 0
Grants [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized under grants		408,000	149,000	508,000	$ 149,000
Grants [Member] \| NIH Research Grants Two [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized under grants		408,000	$ 149,000	508,000	$ 149,000
Research and Development Services [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue		$ 619,000		$ 619,000		$ 687,000
At-The-Market Facility [Member]
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock		3,762,130		3,762,130
Gross proceeds from sale of common stock shares				$ 5,100,000

Stockholders' Equity - Schedule of Stock-based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,274	$ 2,298	$ 2,553	$ 4,350
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	229	384	431	715
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,045	$ 1,914	$ 2,122	$ 3,635

Stockholders' Equity - Stock-based Compensation Expense and Valuation Information - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2018 USD ($)
Class Of Stock [Line Items]
Total unrecognized compensation cost related to unvested stock option grants	$ 10,231,536
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	$ 14,000
Stock options [Member]
Class Of Stock [Line Items]
Total unrecognized compensation cost related, weighted average period	3 years 1 month 20 days
Restricted stock units (RSUs) [Member]
Class Of Stock [Line Items]
Total unrecognized compensation cost related, weighted average period	2 years 9 months 25 days
Unrecognized stock-based compensation expense	$ 4,585,160
Performance-Based Restricted Stock Units [Member]
Class Of Stock [Line Items]
Total unrecognized compensation cost related, weighted average period	1 year 11 months 23 days
Unrecognized stock-based compensation expense	$ 166,075

Stockholders' Equity - Fair Value of Employee Stock Options (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility	73.19%	70.97%	72.98%	76.58%
Risk-free interest rate	2.74%	1.78%	2.75%	1.81%
Expected life of options	6 years	6 years	6 years	6 years
Weighted average grant date fair value	$ 0.73	$ 1.25	$ 0.84	$ 1.73

Stockholders' Equity - Fair Value of Employee Stock Purchase Plan (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility	73.19%	70.97%	72.98%	76.58%
Risk-free interest rate	2.74%	1.78%	2.75%	1.81%
Expected term	6 years	6 years	6 years	6 years
Grant date fair value	$ 0.73	$ 1.25	$ 0.84	$ 1.73
2016 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%	0.00%
Volatility, Minimum	61.35%	43.03%	61.35%	43.03%
Volatility, Maximum	80.23%	74.70%	80.23%	74.70%
Risk-free interest rate, Minimum	1.85%	0.79%	1.85%	0.79%
Risk-free interest rate, Maximum	2.29%	1.10%	2.29%	1.10%
Expected term	6 months	6 months	6 months	6 months
2016 Employee Stock Purchase Plan [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0.00%		0.00%
Grant date fair value	$ 0.30	$ 0.52	$ 0.30	$ 0.52
2016 Employee Stock Purchase Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield			0.00%
Grant date fair value	$ 0.45	$ 1.04	$ 0.45	$ 1.04

Stockholders' Equity - Preferred Stock - Additional Information (Detail)	Sep. 30, 2018 shares
Equity [Abstract]
Preferred stock, shares authorized	25,000,000
Preferred stock, shares outstanding	0

Stockholders' Equity - Common Stock - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		20 Months Ended
	Jul. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 17, 2018	Jul. 26, 2018	Mar. 31, 2018
Class Of Stock [Line Items]
Common stock reserved for future issuance		30,095,159		30,095,159
Issuance of common stock		115,200,421		115,200,421				111,032,957
Common stock, shares authorized		200,000,000		200,000,000				200,000,000
At-The-Market Facility [Member]
Class Of Stock [Line Items]
Issuance of common stock		3,762,130		3,762,130
Certificate of Amendment [Member]
Class Of Stock [Line Items]
Common stock, shares authorized							200,000,000
Equity Offering Sales Agreement [Member]
Class Of Stock [Line Items]
Equity sales agreement expiration date	Mar. 17, 2018
Issuance of common stock						7,304,286
Value of shares sold under equity distribution agreement			$ 1,000,000		$ 4,000,000	$ 19,900,000
Issuance of common stock from stock options exercises, net, Shares			398,728		1,538,217
Equity Offering Sales Agreement [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Common stock reserved for future issuance	26,600,000
2018 Sales Agreement [Member]
Class Of Stock [Line Items]
Equity sales agreement expiration date				Feb. 22, 2021
Issuance of common stock		3,762,130		3,762,130
Value of shares sold under equity distribution agreement				$ 5,100,000
2018 Sales Agreement [Member] \| At-The-Market Facility [Member]
Class Of Stock [Line Items]
Value of shares sold under equity distribution agreement		$ 2,100,000		$ 5,100,000
Issuance of common stock from stock options exercises, net, Shares		1,676,590		3,762,130
Common stock value reserved for future issuance		$ 44,800,000		$ 44,800,000
2018 Sales Agreement [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Common stock value reserved for future issuance		$ 94,800,000		$ 94,800,000

Stockholders' Equity - Restricted Stock Awards, Restricted Stock Units and Performance-Based Restricted Stock Units - Additional Information (Detail)		6 Months Ended
	Aug. 23, 2017 USD ($) Tranche shares	Sep. 30, 2018 Tranche shares	Aug. 15, 2018 shares	Mar. 31, 2018 shares	Apr. 24, 2017 shares
Restricted stock units (RSUs) [Member]
Class Of Stock [Line Items]
Number of shares allocated		2,609,765		2,035,345
Restricted stock units (RSUs) [Member] \| CMO [Member]
Class Of Stock [Line Items]
Number of shares allocated			160,714
Inducement Award Performance-Based Restricted Stock Units [Member]
Class Of Stock [Line Items]
Number of tranches \| Tranche	5
Award vesting percentage		100.00%
Number of tranches expected to vest \| Tranche		0
Grant date fair values of tranches \| $	$ 393,000
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		20.00%
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)	6 Months Ended
	Sep. 30, 2018 $ / shares shares
Restricted stock units (RSUs) [Member]
Class Of Stock [Line Items]
Beginning balance, Unvested, Number of Shares	2,035,345
Granted, Number of Shares	1,759,520
Vested, Number of Shares	(412,368)
Canceled / forfeited, Number of Shares	(772,732)
Ending balance, Unvested, Number of Shares	2,609,765
Beginning balance, Unvested, Weighted Average Price \| $ / shares	$ 2.89
Granted, Weighted Average Price \| $ / shares	1.18
Vested, Weighted Average Price \| $ / shares	2.63
Canceled / forfeited, Weighted Average Price \| $ / shares	2.38
Ending balance, Unvested, Weighted Average Price \| $ / shares	$ 1.94
Performance-Based Restricted Stock Units [Member]
Class Of Stock [Line Items]
Beginning balance, Unvested, Number of Shares	167,058
Granted, Number of Shares	0
Vested, Number of Shares	(41,764)
Canceled / forfeited, Number of Shares	0
Ending balance, Unvested, Number of Shares	125,294
Beginning balance, Unvested, Weighted Average Price \| $ / shares	$ 1.88
Granted, Weighted Average Price \| $ / shares	0
Vested, Weighted Average Price \| $ / shares	1.88
Canceled / forfeited, Weighted Average Price \| $ / shares	0
Ending balance, Unvested, Weighted Average Price \| $ / shares	$ 1.88
Beginning balance, Unvested, Maximum Number of Shares Eligible to be Issued	200,470
Awarded at target, Maximum Number of Shares Eligible to be Issued	0
Vested, Maximum Number of Shares Eligible to be Issued	(41,764)
Forfeited, Maximum Number of Shares Eligible to be Issued	0
Ending balance, Unvested, Maximum Number of Shares Eligible to be Issued	158,706

Stockholders' Equity - Stock Options and Employee Stock Purchase Plan - Additional Information (Detail) - USD ($)			3 Months Ended		6 Months Ended
	Aug. 15, 2018	Apr. 24, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Class Of Stock [Line Items]
Weighted-average remaining contractual term of options exercisable					6 years 18 days
Weighted-average remaining contractual term of options outstanding					6 years 18 days
Number of common stock shares approved under ESPP			30,095,159		30,095,159
Expected life of options			6 years	6 years	6 years	6 years
Inducement Award Agreement [Member] \| CEO [Member]
Class Of Stock [Line Items]
Stock options granted		2,088,212
Period for vesting schedule over start date		4 years
Award vesting conditions					These stock options vest over a four-year period, with a quarter of the option shares vesting on the one-year anniversary of the vesting commencement date and the remaining options shares vesting in equal quarterly installments over the next 12 quarterly periods.
Award vesting percentage					25.00%
Inducement Award Agreement [Member] \| CMO [Member]
Class Of Stock [Line Items]
Stock options granted	974,694
Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Number of common stock shares approved under ESPP			1,500,000		1,500,000
Employee subscription rate			15.00%		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
Shares remaining available for purchase under ESPP			1,230,735		1,230,735

Stockholders' Equity - Summary of Stock Option Activity (Detail)	6 Months Ended
	Sep. 30, 2018 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Beginning balance \| shares	10,132,312
Granted, Options Outstanding \| shares	7,947,694
Cancelled / forfeited, Options Outstanding \| shares	(3,246,759)
Exercised, Options Outstanding \| shares	0
Options Outstanding, Ending balance \| shares	14,833,247
Vested and Exercisable, Options Outstanding \| shares	4,904,840
Weighted-Average Exercise Price, Options Beginning balance \| $ / shares	$ 4.01
Options granted, Weighted-Average Exercise Price \| $ / shares	1.29
Options cancelled / forfeited, Weighted-Average Exercise Price \| $ / shares	5.12
Options exercised, Weighted-Average Exercise Price \| $ / shares	0
Weighted-Average Exercise Price, Options Ending balance \| $ / shares	2.31
Vested and Exercisable, Weighted-Average Exercise Price \| $ / shares	$ 3.66
Aggregate Intrinsic Value, Options Beginning balance \| $	$ 591,082
Aggregate Intrinsic Value, Options \| $	769,236
Vested and Exercisable, Aggregate Intrinsic Value \| $	$ 665,745

Stockholders' Equity - Summary of Warrant Activity (Detail)	6 Months Ended
	Sep. 30, 2018 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Beginning balance \| shares	10,132,312
Granted, Options Outstanding \| shares	7,947,694
Exercised, Options Outstanding \| shares	0
Options Outstanding, Ending balance \| shares	14,833,247
Weighted-Average Exercise Price, Options Beginning balance \| $ / shares	$ 4.01
Granted, Weighted-Average Exercise Price \| $ / shares	1.29
Exercised, Weighted-Average Exercise Price \| $ / shares	0
Weighted-Average Exercise Price, Options Ending balance \| $ / shares	$ 2.31
Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Beginning balance \| shares	220,000
Granted, Options Outstanding \| shares	0
Exercised, Options Outstanding \| shares	0
Cancelled, Options Outstanding \| shares	0
Options Outstanding, Ending balance \| shares	220,000
Weighted-Average Exercise Price, Options Beginning balance \| $ / shares	$ 7.19
Granted, Weighted-Average Exercise Price \| $ / shares	0
Exercised, Weighted-Average Exercise Price \| $ / shares	0
Cancelled, Weighted-Average Exercise Price \| $ / shares	0
Weighted-Average Exercise Price, Options Ending balance \| $ / shares	$ 7.19

Stockholders' Equity - Warrants - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2018 $ / shares
Class Of Stock [Line Items]
Weighted-average remaining contractual term of options exercisable	6 years 18 days
Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share	$ 6.84
Maximum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share	$ 7.62
Warrants [Member]
Class Of Stock [Line Items]
Weighted-average remaining contractual term of options exercisable	8 months 15 days

Stockholders' Equity - Common Stock Reserved for Future Issuance (Detail)	Sep. 30, 2018 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	30,095,159
Equity Incentive Plan 2012 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	11,042,706
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	11,148,149
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	1,230,735
Stock options [Member] \| Inducement Award Agreement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	3,062,906
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	2,449,051
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	160,714
Performance-Based Restricted Stock Units [Member] \| Inducement Award Agreement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	158,706

Collaborative Research, Development, and License Agreements - Additional Information (Detail) - USD ($)	1 Months Ended			3 Months Ended		6 Months Ended
	Apr. 30, 2018	Sep. 30, 2017	Apr. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				$ 943,000	$ 1,355,000	$ 1,632,000	$ 2,345,000
Non-exclusive patent license agreement annual fee				125,000	254,000	245,000	555,000
April 2017 Non-exclusive Research Affiliation Collaborative [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Non-exclusive patent license agreement term			2 years
Proceeds from Non-exclusive patent annual license fee	$ 75,000		$ 75,000
Collaborations and Licenses [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				42,000	260,000	85,000	306,000
Collaborations and Licenses [Member] \| April 2015 Research Collaboration Agreement [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				0	150,000	0	150,000
Collaborations and Licenses [Member] \| April 2015 Multi-year Research Agreement [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				0	0	0	0
Collaborations and Licenses [Member] \| June 2016 Non-exclusive Research Affiliation Collaborative [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				0	18,000	0	35,000
Collaborations and Licenses [Member] \| December 2016 Non-exclusive Research Affiliation Collaborative [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				10,000	9,000	19,000	19,000
Collaborations and Licenses [Member] \| April 2017 Non-exclusive Research Affiliation Collaborative [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				19,000	18,750	38,000	37,500
Collaborations and Licenses [Member] \| April 2017 Non-exclusive Research Affiliation Collaborative [Member] \| Up-front Payment Received [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues				14,000	14,000	29,000	14,000
Collaborations and Licenses [Member] \| September 2017 Agreement [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Total Revenues		$ 50,000		$ 0	$ 50,000	$ 0	$ 50,000
License [Member] \| April 2017 Non-exclusive Research Affiliation Collaborative [Member]
Collaborative Arrangements and Noncollaborative Arrangement Transactions [Line Items]
Non-exclusive patent license agreement annual fee			$ 75,000

Commitments and Contingencies - Additional Information (Detail)	3 Months Ended		6 Months Ended		36 Months Ended	75 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) ft²	Sep. 30, 2017 USD ($)	Jan. 31, 2018 USD ($) ft²	Sep. 30, 2018 USD ($)
Commitments And Contingencies [Line Items]
Rent expense per month			$ 120,000
Base rent escalators	3.00%		3.00%		3.00%	3.00%
Office space under lease agreement \| ft²			45,580
Area of leased office space \| ft²					5,803
Lease term					36 months
Lease rental period start date					Feb. 01, 2015
Lease rental period end date					Jan. 31, 2018
Base rent under the lease					$ 12,000
Leasehold improvements						$ 518,000
Rent expense	$ 326,000	$ 365,000	$ 651,000	$ 731,000
Lease Term For Remainder of Total Rentable Square Footage [Member]
Commitments And Contingencies [Line Items]
Lease expiration date			Sep. 01, 2021
Lease option termination description			option to terminate the lease on or after September 1, 2019 with 9 months prior written notice.
Lease 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			Oct. 31, 2018

Commitments and Contingencies - Future Minimum Annual Operating Lease Payments (Detail) $ in Thousands	Sep. 30, 2018 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Fiscal year ended March 31, 2019	$ 565,411
Fiscal year ended March 31, 2020	1,073,027
Fiscal year ended March 31, 2021	1,104,070
Fiscal year ended March 31, 2022	467,594
Fiscal year ended March 31, 2023	0
Thereafter	0
Total	$ 3,210,102

Related Parties - Additional Information (Detail) - USD ($)	3 Months Ended			6 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cirius Therapeutics, Inc., [Member]
Related Party Transaction [Line Items]
Amount of transactions with related party for providing services			$ 50,000	$ 255,000	$ 50,000
Revenue recognized from related parties agreement		$ 52,000		94,000
Cirius Therapeutics, Inc., [Member] \| Scenario, Forecast [Member]
Related Party Transaction [Line Items]
Amount of transactions with related party for providing services	$ 27,000
Viscient Biosciences [Member]
Related Party Transaction [Line Items]
Amount of transactions with related party for providing services			$ 0		$ 0
Viscient Biosciences [Member] \| Study Materials [Member]
Related Party Transaction [Line Items]
Amount of transactions with related party for providing services				2,000
Revenue recognized from related parties agreement		2,000		2,000
Viscient Biosciences [Member] \| Samsara [Member] \| Primary Human Cell-based Products [Member]
Related Party Transaction [Line Items]
Amount of transactions with related party for providing services				3,000
Revenue recognized from related parties agreement		$ 1,000		$ 3,000
Viscient Biosciences [Member] \| Scenario, Forecast [Member] \| Samsara [Member] \| RNAseq Data Set and Primary Human Cell-based Products [Member]
Related Party Transaction [Line Items]
Amount of transactions with related party for providing services	$ 130,000

Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Nov. 09, 2018	Sep. 30, 2018	Mar. 31, 2018
Subsequent Event [Line Items]
Common stock, shares issued		115,200,421	111,032,957
At-The-Market Facility [Member]
Subsequent Event [Line Items]
Common stock, shares issued		3,762,130
Net proceeds from sale of common stock		$ 5.1
Subsequent Event [Member] \| At-The-Market Facility [Member]
Subsequent Event [Line Items]
Common stock, shares issued	741,298
Net proceeds from sale of common stock	$ 0.8

Stockholders' Equity - Summary of Warrant Activity (Detail)	6 Months Ended
	Sep. 30, 2018 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Beginning balance \| shares	10,132,312
Granted, Options Outstanding \| shares	7,947,694
Exercised, Options Outstanding \| shares	0
Options Outstanding, Ending balance \| shares	14,833,247
Weighted-Average Exercise Price, Options Beginning balance \| $ / shares	$ 4.01
Granted, Weighted-Average Exercise Price \| $ / shares	1.29
Exercised, Weighted-Average Exercise Price \| $ / shares	0
Weighted-Average Exercise Price, Options Ending balance \| $ / shares	$ 2.31
Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Beginning balance \| shares	220,000
Granted, Options Outstanding \| shares	0
Exercised, Options Outstanding \| shares	0
Cancelled, Options Outstanding \| shares	0
Options Outstanding, Ending balance \| shares	220,000
Weighted-Average Exercise Price, Options Beginning balance \| $ / shares	$ 7.19
Granted, Weighted-Average Exercise Price \| $ / shares	0
Exercised, Weighted-Average Exercise Price \| $ / shares	0
Cancelled, Weighted-Average Exercise Price \| $ / shares	0
Weighted-Average Exercise Price, Options Ending balance \| $ / shares	$ 7.19