Ocugen (OCGN) 10-Q 9 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Nov. 07, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	HSGX
Entity Registrant Name	Histogenics Corporation
Entity Central Index Key	1,372,299
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		24,071,029

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 10,798	$ 31,908
Marketable securities	1,821
Prepaid expenses and other current assets	258	173
Total current assets	12,877	32,081
Property and equipment, net	2,814	3,860
Restricted cash	137	137
Total assets	15,828	36,078
Current liabilities:
Accounts payable	827	1,588
Accounts payable due to Intrexon Corporation		360
Accrued expenses	1,518	2,097
Current portion of deferred rent	60	136
Current portion of deferred lease incentive	185	407
Current portion of equipment loan	324	583
Total current liabilities	2,914	5,171
Accrued expenses due to Intrexon Corporation	3,040	3,040
Deferred rent, long-term	289	315
Deferred lease incentive, long-term	527	610
Equipment loan, long-term		178
Warrant liability	13,871	13,197
Total liabilities	20,641	22,511
Commitments and contingencies (Note 5)
Convertible preferred stock and stockholders' equity (deficit):
Convertible preferred stock, $0.01 par value; 30,000 shares authorized, 8,610.5701 and 13,416.4734 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively
Common stock, $0.01 par value; 100,000,000 shares authorized, 22,791,066 and 20,647,612 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	159	159
Additional paid-in capital	196,419	195,181
Accumulated deficit	(201,391)	(181,773)
Total stockholders' equity (deficit)	(4,813)	13,567
Total liabilities and stockholders' equity (deficit)	$ 15,828	$ 36,078

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	22,791,066	20,647,612
Common stock, shares outstanding	22,791,066	20,647,612
Series A Convertible Preferred Stock [Member]
Convertible preferred stock, par value	$ 0.01	$ 0.01
Convertible preferred stock, shares authorized	30,000	30,000
Convertible preferred stock, shares issued	8,610.5701	13,416.4734
Convertible preferred stock, shares outstanding	8,610.5701	13,416.4734

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	3,488	4,880	12,200	16,260
General and administrative	2,225	1,768	6,717	6,141
Total operating expenses	5,713	6,648	18,917	22,401
Loss from operations	(5,713)	(6,648)	(18,917)	(22,401)
Other income (expense):
Interest income (expense), net	39	(20)	114	(55)
Other expense, net	(52)	(130)	(142)	(298)
Warrant expense		(3,056)		(3,056)
Change in fair value of warrant liability	(269)	539	(673)	539
Total other expense, net	(282)	(2,667)	(701)	(2,870)
Net loss	(5,995)	(9,315)	(19,618)	(25,271)
Other comprehensive loss:
Unrealized gain from available for sale securities	1
Comprehensive loss	(5,994)	(9,315)	(19,618)	(25,271)
Net loss attributable to common stockholders- basic and diluted	$ (5,080)	$ (9,234)	$ (16,380)	$ (25,197)
Net loss per common share-basic and diluted	$ (0.23)	$ (0.70)	$ (0.74)	$ (1.90)
Weighted-average shares used to compute loss per common share-basic and diluted	22,552,341	13,297,546	22,219,666	13,279,833

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (19,618)	$ (25,271)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,178	1,267
Amortization of discount of investments	24
Deferred rent and lease incentive	(407)	(400)
Stock-based compensation	1,233	1,080
Change in fair value of warrant	673	(539)
Warrant expense		3,056
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(85)	120
Accrued expenses due to Intrexon Corporation		1,256
Accounts payable	(761)	(358)
Accounts payable due to Intrexon Corporation	(360)	(94)
Accrued expenses	(578)	40
Net cash used in operating activities	(18,701)	(19,843)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(132)	(317)
Proceeds from maturities of marketable securities	6,159
Purchases of marketable securities	(8,004)
Net cash used in investing activities	(1,977)	(317)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock, preferred stock and warrants, net of issuance costs		27,674
Repayments on equipment term loan	(437)	(437)
Proceeds from exercise of stock options	5	2
Net cash (used in) provided by financing activities	(432)	27,239
Net (decrease) increase in cash and cash equivalents	(21,110)	7,079
Cash and cash equivalents-Beginning of period	31,908	30,915
Cash and cash equivalents-End of period	$ 10,798	$ 37,994

Nature of Business

Nature of Business	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	1. NATURE OF BUSINESS Organization Histogenics Corporation (the “Company”) was incorporated under the laws of the Commonwealth of Massachusetts on June 28, 2000 and has its principal operations in Waltham, Massachusetts. In 2006, the Company’s board of directors approved a corporate reorganization pursuant to which the Company incorporated as a Delaware corporation. The Company is a cell therapy company engaged in developing and commercializing products in the musculoskeletal segment of the marketplace. The Company combines cell therapy and tissue engineering technologies to develop products for tissue repair and regeneration and is initially focused on patients suffering from cartilage-derived pain and immobility. The Company’s most advanced product, NeoCart ® On May 13, 2011, the Company completed the acquisition of ProChon Biotech Ltd. (“ProChon”), a privately-held biotechnology company focused on modulating the fibroblast growth factor system for consideration of $2.2 million to enable it to create more effective solutions for tissue regeneration. The acquisition of ProChon provided the Company with access to a significant portfolio of intellectual property, including proprietary cell growth factors, in addition to furthering opportunities for the use of biomaterials to create more effective solutions for regenerating human tissue. The acquisition led to the initial recognition of goodwill, which was subsequently written off in 2011, and intangible assets including IPR&D and a licensing agreement which have been fully-impaired. On December 18, 2014, the Company formed a wholly owned subsidiary, Histogenics Securities Corporation, under the laws of the Commonwealth of Massachusetts. On September 29, 2016, the Company closed a private placement of common stock, preferred stock and warrants, contemplated by a securities purchase agreement dated September 15, 2016, with certain institutional and accredited investors. The net proceeds after deducting placement agent fees and other transaction-related expenses was $27.6 million. See Note 6, Capital Stock, for further discussion of the private placement. Since its inception, the Company has devoted substantially all of its efforts to product development, recruiting management and technical staff, raising capital, starting up production and building infrastructure and has not yet generated revenues from its planned principal operations. Expenses have primarily been for research and development and related administrative costs. The Company is subject to a number of risks. The developmental nature of its activities is such that significant inherent risks exist in the Company’s operations. Principal among these risks are the successful development of therapeutics, successfully enrolling patients in its clinical trials in a timely manner, ability to obtain adequate financing, obtaining regulatory approval for any of its product candidates in any jurisdiction, obtaining adequate reimbursement rates for any of its approved product candidates, compliance with government regulations, protection of proprietary therapeutics, fluctuations in operating results, dependence on key personnel and collaborative partners, adoption of the Company’s products by the physician community, rapid technological changes inherent in the markets targeted, the introduction of substitute products and competition from larger companies. Liquidity The consolidated financial statements have been prepared on a going-concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. As shown in the accompanying consolidated financial statements, the Company had an accumulated deficit at September 30, 2017 of $201.4 million and has incurred losses and cash flow deficits from operations for the nine months ended September 30, 2017 and 2016. The Company has financed operations to date primarily through private placements of equity securities, including the sales of common stock and preferred stock, and the related issuance of warrants in September 2016, the issuance of common stock in the initial public offering completed in December 2014, and borrowings under debt agreements. The Company anticipates that it will continue to incur net losses for the next several years and will require additional capital to complete the filing of a BLA with the FDA and commercialize NeoCart, if approved, and for the future development of its existing product candidates. However, the Company expects that total operating expenses will be lower over the next four quarters than the previous four quarters. As of September 30, 2017, the Company had approximately $12.6 million of cash and cash equivalents and marketable securities. Given the Company’s current development plans, it anticipates that its existing cash and cash equivalents and marketable securities will be not be sufficient to fund its operations beyond the middle of 2018. Accordingly, these factors, among others, raise substantial doubt about the Company’s ability to continue as a going concern. To meet its capital needs, the Company intends to raise additional capital through debt or equity financing or other strategic transactions. However, there can be no assurance that the Company will be able to complete any such transaction on acceptable terms or otherwise. The failure of the Company to obtain sufficient funds on commercially acceptable terms when needed could have a material adverse effect on the Company’s business, results of operations and financial condition. The forecast of cash resources is forward-looking information that involves risks and uncertainties, and the actual amount of our expenses could vary materially and adversely as a result of a number of factors. The Company has based its estimates on assumptions that may prove to be wrong, and the Company’s expenses could prove to be significantly higher than it currently anticipates. Basis of Accounting The consolidated financial statements are unaudited and have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). However, they do not include all of the information and footnotes required by GAAP for complete financial statements. These interim consolidated financial statements, in the opinion of the Company’s management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods ended September 30, 2017 and 2016. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2016, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission (the “SEC”) on March 16, 2017. The consolidated financial statements include the accounts of Histogenics Corporation and its wholly-owned subsidiaries, ProChon and Histogenics Securities Corporation. All significant intercompany accounts and transactions are eliminated in consolidation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES During the nine months ended September 30, 2017, there have been no material changes to the significant accounting policies described in the Company’s audited financial statements as of and for the year ended December 31, 2016, and the notes thereto, which are included in the Annual Report on Form 10-K, except as noted below. Fair Value Measurements The carrying amounts reported in the Company’s consolidated financial statements for cash and cash equivalents, marketable securities, accounts payable, equipment loan, and accrued liabilities approximate their respective fair values because of the short-term nature of these accounts. Fair value is defined as the price that would be received if selling an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Additionally, from time to time, the Company may be required to record at fair value other assets on a nonrecurring basis, such as assets held for sale and certain other assets. These nonrecurring fair value adjustments typically involve the application of lower-of-cost-or-market accounting or write-downs of individual assets. The fair value hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets (Level 1), and the lowest priority to unobservable inputs (Level 3). The Company’s financial assets are classified within the fair value hierarchy based on the lowest level of inputs that is significant to the fair value measurement. The three levels of the fair value hierarchy, and their applicability to the Company’s financial assets, are described below. Level 1 Level 2 Level 3 An adjustment to the pricing method used within either Level 1 or Level 2 inputs could generate a fair value measurement that effectively falls in a lower level in the hierarchy. The Company had no material re-measurements of fair value with respect to financial assets and liabilities, during the periods presented, other than those assets and liabilities that are measured at fair value on a recurring basis. Other than the warrants issued in connection with the private placement transaction which closed on September 29, 2016, the Company had no assets or liabilities classified as Level 3 as of September 30, 2017 and December 31, 2016. Transfers are calculated on values as of the transfer date. There were no transfers between Levels 1, 2 and 3 during the nine months ended September 30, 2017 and twelve months ended December 31, 2016. The fair value of the warrants is considered a Level 3 valuation and was determined using a Monte Carlo simulation model. This model incorporated several assumptions at each valuation date including: the price of the Company’s common stock on the date of valuation, the historical volatility of the price of the Company’s common stock, the remaining contractual term of the warrant and estimates of the probability of a fundamental transaction occurring (See Note 6 for further discussion of the private placement). The Company’s financial instruments as of September 30, 2017 consisted primarily of cash and cash equivalents, marketable securities and warrant liability. The Company’s financial instruments as of December 31, 2016 consisted primarily of cash and cash equivalents and warrant liability. As of September 30, 2017, and December 31, 2016, the Company’s financial assets recognized at fair value consisted of the following: Description Total Quoted prices in active markets (Level 1) Significant other observable (Level 2) Significant unobservable inputs (Level 3) (in thousands) September 30, 2017 Assets: Cash Equivalents Money market funds $ 4,603 $ 4,603 $ — $ — Marketable securities: Asset-backed securities 900 — 900 — Corporate notes 921 — 921 — Total $ 6,424 $ 4,603 $ 1,821 $ — Liabilities: Warrant liability $ 13,871 $ — $ — $ 13,871 December 31, 2016 Assets: Money market funds $ 30,318 $ 30,318 $ — $ — Liabilities: Warrant liability $ 13,198 $ — $ — $ 13,198 The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs: As of September 30, 2017 (in thousands) Beginning balance, December 31, 2016 $ 13,198 Change in fair value of warrant liability 673 Ending balance $ 13,871 Cash and Cash Equivalents The Company considers all highly liquid securities with original maturities of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents are comprised of funds in money market accounts. Marketable Securities The Company classifies marketable securities with a remaining maturity when purchased of greater than three months as available for sale. The Company considers all available for sale securities, including those with maturity dates beyond 12 months, as available to support current operational liquidity needs and therefore classifies all securities including those with maturity dates beyond 90 days at the date of purchase as current assets within the consolidated balance sheets. Available for sale securities are maintained by the Company’s investment managers and may consist of commercial paper, high-grade corporate notes, U.S. Treasury securities, U.S. government agency securities, and certificates of deposit. Available for sale securities are carried at fair value with the unrealized gains and losses included in other comprehensive income (loss) as a component of stockholders’ equity (deficit) until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expense over the life of the instrument. Realized gains and losses are determined using the specific identification method and are included in other income (expense). If any adjustment to fair value reflects a decline in value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other-than-temporary” and, if so, marks the investment to market through a charge to the Company’s consolidated statement of operations and comprehensive loss. The following table summarizes the available for sale securities held at September 30, 2017: Description Amortized Unrealized Gains Unrealized Losses Fair (in thousands) Asset-backed securities $ 900 $ — $ — $ 900 Corporate notes 921 — — 921 Total $ 1,821 $ — $ — $ 1,821 The Company did not hold any available for sale securities prior to the first quarter of 2017. The amortized cost of available for sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At September 30, 2017, the balance in the Company’s accumulated other comprehensive loss was composed solely of activity related to the Company’s available for sale marketable securities. There were no sales of available for sale securities during the quarter ended September 30, 2017. The aggregate fair value of available for sale securities held by the Company for less than twelve months as of September 30, 2017 was $1.8 million. The Company determined that there was no material change in the credit risk of any of its investments. As a result, the Company determined it did not hold any investments with any other-than-temporary impairment as of September 30, 2017. The weighted average maturity of the Company’s portfolio was approximately one month at September 30, 2017. Stock-Based Compensation The Company accounts for stock options and restricted stock based on their grant date fair value and recognizes compensation expense on a straight-line basis over their vesting period. The Company estimates the fair value of stock options as of the date of grant using the Black-Scholes option pricing model, with the exception of stock options that include a market condition, and restricted stock based on the fair value of the underlying common stock as of the date of grant or the value of the services provided, whichever is more readily determinable. The Company, in conjunction with adoption of ASU 2016-09- Stock Compensation: Improvements to Employee Share-Based Payment Accounting For stock option grants with vesting triggered by the achievement of performance-based milestones, the expense is recorded over the remaining service period after the point when the achievement of the milestone is probable or the performance condition has been achieved. For stock option grants with both performance-based milestones and market conditions, expense is recorded over the derived service period after the point when the achievement of the performance-based milestone is probable or the performance condition has been achieved. For stock option grants with market conditions, the expense is calculated using the Monte Carlo model based on the grant date fair value of the option and is recorded on a straight line basis over the requisite service period, which represents the derived service period and accelerated when the market condition is satisfied. The Company did not issue awards with market conditions during the nine months ended September 30, 2017. The Company accounts for stock options and restricted stock awards to non-employees using the fair value approach. Stock options and restricted stock awards to non-employees are subject to periodic revaluation over their vesting terms. Warrant Accounting As noted in Note 6, Capital Stock, the Company classifies a warrant to purchase shares of its common stock as a liability on its consolidated balance sheet if the warrant is a free-standing financial instrument that may require the Company to transfer consideration upon exercise. Each warrant of this type is initially recorded at fair value on date of grant using the Monte Carlo simulation model and net of issuance costs, and is subsequently re-measured to fair value at each subsequent balance sheet date. Changes in fair value of the warrant are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. The Company will continue to adjust the liability for changes in fair value until the earlier of the exercise or expiration of the warrant. Recent Accounting Pronouncements In November 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The standard requires restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods shown on the statement of cash flows. The new standard is effective for the Company on January 1, 2018 using a retrospective transition method to each period presented. Early adoption is permitted. We are currently evaluating the timing of our adoption and the expected impact that this standard could have on our consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Shared-Based Payment Accounting. This standard provides guidance on accounting for employee share-based payments. This guidance addresses several aspects of the accounting for share-based payment award transactions, including: (a) income tax consequences; (b) classification of awards as either equity or liabilities; and (c) classification on the statement of cash flows. This standard will be effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company has concluded that this guidance has no material impact on the presentation of its results of operations, financial position and disclosures. In February 2016, the FASB issued ASU No. 2016-02- Leases (Topic 842). This standard requires companies to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leased assets. ASU 2016-02 will be effective for the Company in the first quarter of 2019, with early adoption permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-02 will have on the Company’s consolidated financial statements and related disclosures. In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. This standard provides guidance that requires management to assess an entity’s ability to continue as a going concern every reporting period, and provide certain disclosures if management has substantial doubt about the entity’s ability to operate as a going concern, or an express statement if not, by incorporating and expanding upon certain principles that are currently in U.S. auditing standards. This guidance is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. The Company adopted this guidance in the fourth quarter of 2016 and made the relevant disclosures in the consolidated financial statements and related footnotes. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In July 2015, the FASB issued a one-year deferral of the effective date of the new revenue recognition standard. The new guidance will be effective for the Company’s first quarter of fiscal year 2018 and early application for fiscal year 2017 is permitted. The Company’s adoption of this guidance is not expected to have a material impact on the consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting. This standard provides guidance on changes to the terms or conditions of a share based payment award that requires an entity to apply modification accounting. The guidance is effective for annual periods beginning after December 15, 2017, and for interim periods and annual periods thereafter. The Company is currently evaluating the impact that the adoption of this guidance will have on the Company’s consolidated 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. This update addresses the complexity of accounting for certain financial instruments with down round features. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company has concluded that this guidance has no impact on the presentation of its results of operations, financial position and disclosures.

Loss Per Common Share

Loss Per Common Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Loss Per Common Share	3. LOSS PER COMMON SHARE The Company computes basic and diluted loss per share using a methodology that gives effect to the impact of outstanding participating securities (the “two-class method”). For the three and nine months ended September 30, 2017 and 2016, there was no dilution attributed to the weighted-average shares outstanding in the calculation of diluted loss per share. Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (In thousands, except share and per share data) Numerator: Net loss $ (5,995 ) $ (9,315 ) $ (19,618 ) $ (25,271 ) Net loss attributable to Series A Preferred Stock (a) (915 ) (81 ) (3,238 ) (74 ) Loss attributable to common stockholders—basic and diluted $ (5,080 ) $ (9,234 ) $ (16,380 ) $ (25,197 ) Denominator: Weighted-average number of common shares used in loss per share—basic and diluted 22,552,341 13,297,546 22,219,666 13,279,833 Loss per share—basic and diluted $ (0.23 ) $ (0.70 ) $ (0.74 ) $ (1.90 ) (a) The Series A Preferred Stock participates in income and losses. The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding, as they would be anti-dilutive (in common stock equivalent shares): For the Three and Nine Months Ended September 30, 2017 2016 Unvested restricted stock and options to purchase common stock 2,194,630 882,887 Series A preferred stock unconverted 3,826,920 — Warrants exercisable into common stock 13,633,070 13,633,070

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment	4. PROPERTY AND EQUIPMENT Property and equipment consisted of the following: September 30, December 31, 2017 2016 (in thousands) Office equipment $ 279 $ 266 Laboratory equipment 4,511 4,443 Leasehold improvements 7,712 7,683 Construction in progress 779 759 Software 96 96 Total property and equipment 13,377 13,247 Less: accumulated depreciation (10,563 ) (9,387 ) Property and equipment, net $ 2,814 $ 3,860 Depreciation expense related to property and equipment amounted to $389 and $404 for the three months ended September 30, 2017 and 2016, respectively, and $1,178 and $1,267 for the nine months ended September 30, 2017 and 2016, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	5. COMMITMENTS AND CONTINGENCIES Operating Leases The Company leases its office and research facilities in Waltham and Lexington, Massachusetts under non-cancellable operating leases. The Lexington, Massachusetts facility lease expires in June 2023. The Waltham, Massachusetts facility lease was extended in April 2017. The effective date of the extension is January 2018. Under the terms of the extension, the lease will expire in December 2024 with one extension term of five years. Terms of the agreements generally provide for an initial rent-free period and future rent escalation, and provide that in addition to minimum lease rental payments, the Company is responsible for a pro-rata share of common area operating expenses. The Company’s wholly-owned subsidiary, ProChon, leased a facility in Woburn, Massachusetts which expired in 2016 and was not renewed. Rent expense under operating lease agreements amounted to approximately $248 and $248 for the three months ended September 30, 2017 and 2016, respectively, and $743 and $742 for the nine months ended September 30, 2017 and 2016, respectively. As an inducement to enter into its Waltham and Lexington facility leases, the lessors agreed to provide the Company with construction allowances of up to $3,184 and $996, respectively, towards the total cost of tenant improvements. The Company has recorded these costs in the consolidated balance sheets as leasehold improvements, with the corresponding liability as deferred lease incentive. The liability is amortized on a straight-line basis over the term of the leases as a reduction of rent expense. The Waltham lease renewal effective January 1, 2018 provides for a tenant improvement allowance not to exceed $0.9 million, of which $0.5 million can be applied to future rental payments. License Agreements From time to time, the Company enters into various licensing agreements whereby the Company may use certain technologies in conjunction with its product research and development. Licensing agreements and the Company’s commitments under the agreements are as follows: Hydrogel License In May 2005, the Company entered into an exclusive license agreement with Angiotech Pharmaceuticals (US), Inc. for the use of certain patents, patent applications, and knowledge related to the manufacture and use of a hydrogel material in conjunction with NeoCart and certain other products (“Hydrogel License Agreement”). As of September 30, 2017, the Company has paid an aggregate $3.2 million in commercialization milestones under the terms of the Hydrogel License Agreement, which have been expensed to research and development. Under the terms of the Hydrogel License Agreement, the Company’s future commitments include: • A one-time $3.0 million payment upon approval of an eligible product by the FDA; and • Single digit royalties on the net sales of NeoCart and certain other future products. Tissue Regeneration License In April 2001, the Company entered into an exclusive license agreement with The Board of Trustees of the Leland Stanford Junior University (“Stanford University”) for the use of certain technology to develop, manufacture and sell licensed products in the field of growth and regeneration of cartilage (“Tissue Regeneration License Agreement”). The term of the Tissue Regeneration License Agreement extends to the expiration date of Stanford University’s last to expire domestic or foreign patents. As of September 30, 2017, the Company has paid an aggregate $0.8 million in patent reimbursement costs, royalty fees, and commercialization milestone payments under the terms of the Tissue Regeneration License Agreement, which have been recorded to research and development expense. Under the terms of the Tissue Regeneration License Agreement, the Company’s future commitments include: • A one-time $0.3 million payment upon approval of an eligible product by the FDA; • An annual minimum non-refundable royalty fee of $10 thousand for the life of the license that may be used to offset up to 50% of the earned royalty below; and • Low single digit royalties on net sales. Honeycomb License In March 2013, the Company entered into a license agreement with Koken Co., Ltd. (“Koken”) and paid a fee for a non-exclusive, non-transferable and non-sublicensable right to use its know-how related to the process for manufacturing atelocollagen honeycomb sponge materials, which is used in scaffolds (the “Honeycomb License Agreement”). Under the terms of the Honeycomb License Agreement, future commitments will be based on the amount of materials supplied to the Company and may vary from period to period over the term of the agreement. Tissue Processor Sub-License In December 2005, the Company entered into an exclusive agreement to sub-license certain technology from Purpose, Co. (“Purpose”), which is owned by a stockholder of the Company (“Sub-License Agreement”). Purpose entered into the original license agreement (“Original Agreement”) with Brigham and Women’s Hospital, Inc. (“Brigham and Women’s”) in August 2001. The Original Agreement shall remain in effect for the term of the licensed patents owned by Brigham and Women’s unless extended or terminated as provided for in the agreement. The technology is to be used to develop, manufacture, use and sell licensed products that cultivate cell or tissue development. The Sub-License Agreement extends to the expiration date of the last to expire domestic or foreign patents covered by the agreement. As of September 30, 2017, the Company has paid an aggregate $1.0 million in royalty and sub-license payments under the terms of the Sub-License Agreement. The Sub-License Agreement was amended and restated in June 2012. Under the amended and restated agreement, the Company made Purpose the sole supplier of equipment the Company uses in its manufacturing processes, and granted Purpose distribution rights of the Company’s products for certain territories. In exchange, Purpose allowed for the use of its technology (owned or licensed) and manufactured and serviced exogenous tissue processors used by the Company. Under the terms of the agreement, as amended, Purpose granted the Company: (a) exclusive rights to all of Purpose’s technology (owned or licensed) related to the exogenous tissue processors, (b) continued supply of exogenous tissue processors during the Company’s clinical trials, and (c) rights to manufacture the exogenous tissue processors at any location the Company chooses. In exchange for such consideration, the Company granted Purpose an exclusive license in Japan for the use of all of the Company’s technology and made a payment of $0.3 million to reimburse Purpose for development costs on a next generation tissue processor. In May 2016, the Original Agreement was amended whereby the Company acquired the development and commercialization rights to NeoCart for the Japanese market from Purpose. Under the terms of the amended agreement, the Company assumes sole responsibility for and rights to the development and commercialization of NeoCart in Japan. In exchange for the transfer of development and commercialization rights, the Company will pay a success-based milestone to Purpose upon conditional approval of NeoCart in Japan, as well as commercial milestones and a low single digit royalty on Japanese sales of NeoCart, upon full approval, if any, in Japan. In addition to the above, the Company’s future commitments under the terms of the Original Agreement and Sub-License Agreement include: • A minimum non-refundable annual royalty fee of $20 thousand, for the life of the license; • An additional, non-refundable annual royalty fee of $30 thousand from 2016 through 2019; • $10.2 million in potential milestone payments; and • Low single digit royalties on net sales of a licensed product. The OCS Agreement In connection with its research and development, the Company received grants from the Office of Chief Scientist of the Ministry of Industry and Trade in Israel (“OCS”) in the aggregate of $1.1 million for funding the fibroblast growth factor (“FGF”) program. In consideration for this grant, the Company is committed to pay royalties at a rate of 3% to 5% of the sales of sponsored products developed using the grant money, up to the amount of the participation payments received. The Company committed to pay up to 100% of grants received plus interest according to the LIBOR interest rate if the sponsored product is produced in Israel. If the manufacturing of the sponsored product takes place outside of Israel, the royalties can increase up to, but no more than, 300% of grants received plus interest based on the LIBOR interest rate, depending on the percentage of the manufacturing of sponsored product that takes place outside of Israel. Engineering Agreement The Company entered into an agreement with a development corporation to purchase a multi-unit bioreactor system. Pursuant to the agreement, as of September 30, 2017, the Company made total payments in an aggregate amount of $0.6 million, of which $0.2 million was made in 2016 after acceptance of the final product. There are no additional payments due under this agreement. Collagen Supply Agreement In September 2015, the Company entered into an agreement with Collagen Solutions (UK) Limited (the “Supplier”) to purchase soluble collagen that meets specifications provided by the Company. The initial term of the agreement is three years and will automatically renew from year to year thereafter unless otherwise terminated with at least 180 days’ notice by either party. In February 2017, the Company entered into an amendment with the Supplier. Pursuant to the amendment, the Company agreed to pay the Supplier approximately $0.1 million in exchange for eliminating the minimum annual order of material and/or services and any other amounts due Supplier. The payment of $0.1 million will be made over the 18 months following the date of the amendment. As of September 30, 2017, the Company has paid $30 thousand under the terms of the amendment. The remaining amount of $70 thousand is expected to be paid over the next 9 months.

Capital Stock

Capital Stock	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Capital Stock	6. CAPITAL STOCK On September 29, 2016, the Company closed the private placement contemplated by the securities purchase agreement (the “Purchase Agreement”), dated September 15, 2016, between the Company and certain institutional and accredited investors in which the Company received gross proceeds of $30.0 million (the “Private Placement”). The net proceeds after deducting placement agent fees and other transaction-related expenses was $27.6 million. At the closing, the Company issued 2,596,059 shares of the Company’s common stock at a per share price of $2.25 and 24,158.8693 shares of the Company’s newly-created Series A Convertible Preferred Stock (“Series A Preferred Stock”), which are convertible into approximately 10,737,275 shares of common stock. As of September 30, 2017, there were 8,610.5701 shares of Series A Preferred Stock outstanding, which remain convertible into 3,826,920 shares of the Company’s common stock. As part of the Private Placement, the investors received warrants to purchase up to 13,333,334 shares of the Company’s common stock at an exercise price of $2.25 per share. The placement agent for the Private Placement, H.C. Wainwright & Co. LLC (“HCW”), and certain of its affiliates were also granted warrants to purchase 133,333 shares of the Company’s common stock with an exercise price of $2.25 per share in exchange for the services provided by HCW. The placement agent warrants were considered a financing cost of the Company and included in warrant expense within the consolidated statements of operations. The warrants include a cashless-exercise feature that may be exercised solely in the event there is no effective registration statement, or no current prospectus available for, the resale of the shares of common stock underlying the warrants as of the six-month anniversary of the closing of the Private Placement. Upon a fundamental transaction, the holders of the warrant may require the Company to purchase any unexercised warrants in an amount equal to the Black-Scholes value of the warrant. A fundamental transaction is defined as a merger, sale of assets, sale of the Company, recapitalization of stock and a sale of stock whereby any owner after the transaction would own greater than 50% of the outstanding common stock in the Company. The warrants became exercisable following approval of the Private Placement by our stockholders in the fourth quarter of 2016 and expire five years after the date of such stockholder approval. The Company determined the warrants are classified as a liability on the consolidated balance sheet because they contain a provision whereby in a fundamental transaction (as described above), the holder can elect to receive either the amount they are entitled to on an as-if-exercised basis or an amount based on the Black-Scholes value of the warrants at the time of the fundamental transaction. At the issuance date, the warrants were recorded at the fair value of $30.7 million and approximately $0.4 million excess of the fair value of the liability recorded for these warrants over the proceeds received was recorded as a charge to earnings in the third quarter of 2016 and included in warrant expense within the consolidated statement of operations. In connection with the Private Placement, the Company incurred $3.1 million in warrant expense which was included within the consolidated statements of operations. Concurrent with the closing of the Private Placement, the Company’s Certificate of Incorporation was amended by the filing of a Certificate of Designation to create the Series A Preferred Stock. The Company issued 24,158.8693 shares of the newly created Series A Preferred Stock which are convertible into approximately 10,737,275 shares of common stock. The Series A Preferred Stock has a par value of $0.01 and each share is convertible into 444.44 shares of common stock, at a conversion price of $2.25 per share, at the option of the holder. The Series A Preferred Stock has no voting rights and is only entitled to dividends as declared on an as-converted basis. The Series A Preferred Stock contains no liquidation preferences or redemption rights and shares in distributions of the Company on an as-converted basis with the common stock. The Series A Preferred Stock shall not be converted if, after giving effect to the conversion, the holder and its affiliated persons would own beneficially more than 4.99% of our common stock (subject to adjustment up to 9.99% solely at the holder’s discretion upon 61 days’ prior notice to us or, solely as to a holder, if such limitation is waived by such holder upon execution of the private placement agreement). As part of the Private Placement, affiliates of certain members of the Company’s Board of Directors purchased an aggregate of 283,046 shares of common stock, an aggregate of 2,563.1439 shares of Series A Preferred Stock and received warrants to purchase up to 1,422,221 shares of common stock at an exercise price of $2.25 per share in the Private Placement. These amounts are included in the amounts noted above.

Warrants

Warrants	9 Months Ended
	Sep. 30, 2017
Text Block [Abstract]
Warrants	7. WARRANTS Investor Warrants In September 2016, in connection with the Private Placement, the Company issued common stock warrants to the investors to purchase up to 13,333,334 shares of our common stock at an exercise price of $2.25 per share. The warrants include a cashless-exercise feature that may be exercised solely in the event there is no effective registration statement registering, or no current prospectus available for, the resale of the shares of common stock underlying the warrants as of the six-month anniversary of the closing of the Private Placement. The warrants became exercisable following approval of the Private Placement by our stockholders in the fourth quarter of 2016 and expire five years after the date of such stockholder approval. The warrants were valued at $2.28 using a Monte Carlo simulation and are marked-to-market on a quarterly basis with the change in value recorded as warrant expense or income on the consolidated statements of operations. Placement Agent Warrants In September 2016, in connection with the Private Placement, the Company issued HCW and certain of its affiliates warrants for the purchase of 133,333 shares of common stock at an exercise price of $2.25 per share. The HCW warrants became exercisable following approval of the Private Placement by our stockholders in the fourth quarter of 2016 and expire five years after the date of such stockholder approval. The warrants were valued at $2.28 per share using a Monte Carlo simulation and are marked-to-market on a quarterly basis with the change in value recorded as warrant expense or income on the consolidated statements of operations. Affiliates of an Advisor Warrant In July, 2012, the Company issued warrants to purchase its common stock to affiliates of an advisor. The warrants provide the holders with the right to purchase an aggregate of 161,977 shares of the Company’s common stock at a per share exercise price of $0.01. The warrants are exercisable, in whole or in part, immediately and may be exercised on a cashless basis. The warrants expire on the tenth anniversary of issuance. The fair value of the warrants as of July 20, 2012 was $117 thousand and was estimated using the Black-Scholes option pricing model with the following inputs: (a) risk-free interest rate of 0.22%; (b) implied volatility of the Company’s common stock of 99%; and (c) the expected term to a liquidity event of 1.7 years. The fair value was recorded as a reduction to Series A Preferred Stock and a credit to additional paid-in capital. In December, 2014, the Company completed its initial public offering and warrants for 5,839 shares of common stock were surrendered to partially settle a related liability and common stock was issued by the Company to Purpose for the warrant shares surrendered. As of September 30, 2017 and December 31, 2016, warrants to purchase an aggregate of 156,138 shares of the Company’s common stock at an exercise price of $0.01 were outstanding. Consulting Agreement Warrant In March 2015, in connection with a consulting agreement entered into for an interim chief financial officer, the Company issued a common stock warrant as compensation to the consulting firm. The warrant provides the holder with the right to purchase an aggregate of 7,398 shares of the Company’s common stock at a per share exercise price of $9.75, the closing price of the Company’s common stock on the date of issuance. The warrant vested and became exercisable in monthly installments over 24 months beginning September 30, 2015 and expires on the tenth anniversary of issuance. The warrant is equity classified and accounted for using the fair value approach. The fair value of the warrant is estimated using the Black-Scholes option pricing model and is subject to re-measurement at each reporting period until the measurement date is reached. On December 21, 2015, the Company terminated the consulting agreement resulting in the forfeiture of 50% (3,699) of the shares eligible for exercise under the warrant. The remaining 3,699 shares were vested and exercisable on September 30, 2017 and December 31, 2016. Equipment Line of Credit Warrant In July 2014, the Company granted Silicon Valley Bank a warrant to purchase 6,566 shares of common stock at a per share exercise price of $7.99 as discussed in Note 10. The warrant is exercisable, in whole or in part, immediately and may be exercised on a cashless basis and expires on the tenth anniversary of issuance. The fair value of the warrant as of July 9, 2014 was estimated at $51 thousand with the following inputs: (a) risk-free interest rate of 2.58%; (b) implied volatility of the Company’s common stock of 87%; (c) the expected term of 10 years. The fair value of the warrant was recorded as a debt issuance cost with a corresponding credit to additional paid-in capital.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	8. STOCK-BASED COMPENSATION Stock option activity under the Company’s 2012 Equity Incentive Plan (the “2012 Plan”) and 2013 Equity Incentive Plan (the “2013 Plan”) for the nine months ended September 30, 2017 is summarized as follows: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2016 1,577,016 $ 5.95 Granted 860,000 1.72 Exercised (7,497 ) 0.76 Cancelled (234,889 ) 4.27 Outstanding at September 30, 2017 2,194,630 $ 4.48 8.3 $ 362 Vested and expected to vest at September 30, 2017 2,027,533 $ 4.60 8.3 $ 327 Exercisable at September 30, 2017 934,872 $ 5.91 7.6 $ 120 As of September 30, 2017, the unrecognized compensation cost related to outstanding options was $1.7 million and is expected to be recognized as expense over approximately 1.81 years. As of September 30, 2017, the weighted average grant date fair value of vested options was $3.96 and the weighted average grant date fair value of options outstanding was $2.76. The weighted average grant date fair value per share of employee option grants was $1.14 and $2.47 for the three months ended September 30, 2017 and 2016, respectively, and $1.01 and $1.40 for the nine months ended September 30, 2017 and 2016, respectively. Restricted stock awards under the 2012 Plan and 2013 Plan for the nine months ended September 30, 2017 are summarized as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2016 1,889 $ 0.83 Vesting of restricted stock (1,889 ) 0.83 Unvested at September 30, 2017 — $ — Stock-Based Compensation Expense The Company granted stock options to employees during the three and nine months ended September 30, 2017 and 2016. The Company estimates the fair value of stock options as of the date of grant using the Black-Scholes option pricing model and restricted stock based on the stock price, with the exception of those stock options that included a market condition. The Company estimates the fair value of stock options that include a market condition using a Monte-Carlo model. Stock options and restricted stock issued to non-board member, non-employees are accounted for using the fair value approach and are subject to periodic revaluation over their vesting terms. Stock-based compensation expense amounted to $0.4 million and $0.4 million for the three months ended September 30, 2017 and 2016, respectively, and $1.2 million and $1.1 million for the nine months ended September 30, 2017 and 2016, respectively. The allocation of stock-based compensation for all options granted and restricted stock awards is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands) (in thousands) Research and development $ 86 $ 126 $ 326 $ 364 General and administrative 283 309 907 716 Total stock-based compensation expense $ 369 $ 435 $ 1,233 $ 1,080 Stock-based compensation by award type is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands) (in thousands) Stock options $ 369 $ 434 $ 1,233 $ 1,078 Restricted stock — 1 — 2 Total stock-based compensation expense $ 369 $ 435 $ 1,233 $ 1,080 The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Risk-free interest rate 1.95 % 1.36 % 2.03 % 1.39 % Expected volatility 60.0 % 85.2 % 63.1 % 59.7 % Expected term (in years) 6.08 6.08 6.08 6.08 Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 % The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the non-employee stock option grants were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Risk-free interest rate 1.35 % 1.53 % 1.28 % 1.59 % Expected volatility 59.7 % 63.2 % 63.0 % 63.6 % Expected term (in years) 6.08 6.97 6.08 7.00 Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 %

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	9. INCOME TAXES Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets.

Equipment Loan Payable

Equipment Loan Payable	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Equipment Loan Payable	10. EQUIPMENT LOAN PAYABLE As of September 30, 2017 and December 31, 2016, the Company had the following outstanding borrowing obligations: September 30, December 31, 2017 2016 (in thousands) Silicon Valley Bank Equipment Loan Payable $ 324 $ 761 Less: current portion (324 ) (583 ) Long-term debt, net $ — $ 178 In July 2014, the Company entered into a loan and security agreement with Silicon Valley Bank, which provides for a line of credit to finance certain equipment purchases up to an aggregate of $1.8 million through March 31, 2015. The line has been fully drawn and is payable in 36 monthly installments of principal and interest, with an annual interest rate of 2.75% plus the greater of 3.25% and the prime rate in effect at the time of each draw, as published in the Wall Street Journal. The outstanding balance on the line of credit is secured by a first priority lien over all equipment purchased using the line of credit. In accordance with the terms of the equipment line of credit, the Company issued a warrant to Silicon Valley Bank in July 2014 to purchase 6,566 shares of its common stock at an exercise price per share of $7.99 as discussed in Note 7. The equipment line of credit includes customary operating but non-financial covenants, including limitations on the Company’s ability to incur additional indebtedness, issue dividends, sell assets, engage in any business other than its current business, merge or consolidate with other entities, create liens on its assets, make investments, repurchase stock in certain instances, enter into transactions with affiliates, make payments on subordinated indebtedness and transfer or encumber any collateral securing the debt. As of September 30, 2017 and December 31, 2016 the Company was in compliance with all required covenants. The scheduled maturities of the Company’s debt are as follows: September 30, 2017 (in thousands) December 31, 2017 $ 146 May 31, 2018 178 Total $ 324

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Parties	11. RELATED PARTIES Intrexon Corporation In September 2014, the Company entered into an Exclusive Channel Collaboration Agreement (the “Collaboration Agreement”) with Intrexon Corporation (“Intrexon”) to use Intrexon’s proprietary technology for the development and commercialization of allogeneic cell therapeutics (the “Collaboration Products”) to treat or repair damaged articular hyaline cartilage in humans. The term of the Collaboration Agreement commenced upon the effective date, September 30, 2014, and continues until either written notice of termination is given by the Company within ninety days, or if either party creates a material breach that cannot be remedied within sixty days. Under the terms of the Collaboration Agreement, the Company is solely responsible for the costs to develop and commercialize any Collaboration Products with the following exceptions: (i) the establishment of certain manufacturing capabilities and facilities; (ii) the cost of basic research related to Intrexon’s proprietary technology outside of costs related to the Collaboration Products; (iii) payments related to certain in-licensed third party IP; (iv) the costs of filing, prosecution and maintenance of Intrexon patents; and (v) any other costs mutually agreed upon as being the responsibility of Intrexon. As partial consideration, the Company will pay commercialization milestones totaling $12 million, if and when achieved, and sales milestones totaling $22.5 million, if and when achieved. The milestone payments are payable in cash or shares of the Company’s common stock at the option of the Company. In the event the Company is sold prior to making any of these milestone payments and the Collaboration Agreement is transferred in the sale, the milestone payments would be payable in cash. The Company is also required to make low double digit royalty payments to Intrexon on any gross profit arising from the sale of Collaboration Products and to pay an intermediate double digit percentage of any sublicensing revenue it receives. Under the terms of the Collaboration Agreement, the Company reimburses Intrexon for 50% of the product research and development costs with the remaining 50% due after acceptance by the FDA or equivalent regulatory authority of an Investigational New Drug Application or equivalent regulatory filing of a collaboration product or upon 90 day written notice of cancellation by the Company. There were no expenses incurred under the collaboration for the nine months ended September 30, 2017. For the nine months ended September 30, 2016, total incurred expenses were $2.3 million. The total accrued expenses due to Intrexon at September 30, 2017 and December 31, 2016 were $3.0 million and $3.0 million, respectively. These expenses were included in research and development in the consolidated statements of operations. Purpose, Co. In June 2012, the Company entered into an agreement with Purpose to amend its previous agreements. In the previous agreements, Purpose granted the Company a perpetual license to its patents related to its exogenous tissue processor which is used in the development of the Company’s products. In exchange, the Company granted Purpose a perpetual license to all of the Company’s biotechnology and biomaterial for use in Japan. The agreement provided for Purpose to manufacture and sell machinery to the Company for cost until the Company’s products become commercially viable. The Company also agreed to pay royalties on any third-party revenue generated using Purpose’s licensed technology. Under the June 2012 amendment, the Company received exclusive rights to all of Purpose’s technology related to the exogenous tissue processor, continued supply of exogenous tissue processors during the Company’s clinical trials, and rights to manufacture the exogenous tissue processors at any location the Company chooses. In exchange for such consideration, the Company named Purpose the sole manufacturer of equipment and also clarified the geographic territories of the exclusive license that Purpose was granted for use of the Company’s technology. In addition, the Company agreed to reimburse Purpose for $0.3 million of development costs on a next generation tissue processer. Refer to the discussion under Note 5, Tissue Processor Sub-License In May 2016, the Company acquired the development and commercialization rights to NeoCart for the Japanese market from Purpose. Under the terms of the amended agreement, the Company assumes sole responsibility for and rights to the development and commercialization of NeoCart in Japan. In exchange for the transfer of development and commercialization rights, the Company will pay a success-based milestone to Purpose upon conditional approval of NeoCart in Japan, as well as commercial milestones and a low single digit royalty on Japanese sales of NeoCart, upon full approval, if any, in Japan. The Company paid Purpose $0.1 million and $0.1 million in the nine months ended September 30, 2017 and 2016, respectively. Board of Director Affiliates. Affiliates of certain members of the Company’s Board of Directors participated in the Private Placement as described in Note 6.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Fair Value Measurements	Fair Value Measurements The carrying amounts reported in the Company’s consolidated financial statements for cash and cash equivalents, marketable securities, accounts payable, equipment loan, and accrued liabilities approximate their respective fair values because of the short-term nature of these accounts. Fair value is defined as the price that would be received if selling an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Additionally, from time to time, the Company may be required to record at fair value other assets on a nonrecurring basis, such as assets held for sale and certain other assets. These nonrecurring fair value adjustments typically involve the application of lower-of-cost-or-market accounting or write-downs of individual assets. The fair value hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets (Level 1), and the lowest priority to unobservable inputs (Level 3). The Company’s financial assets are classified within the fair value hierarchy based on the lowest level of inputs that is significant to the fair value measurement. The three levels of the fair value hierarchy, and their applicability to the Company’s financial assets, are described below. Level 1 Level 2 Level 3 An adjustment to the pricing method used within either Level 1 or Level 2 inputs could generate a fair value measurement that effectively falls in a lower level in the hierarchy. The Company had no material re-measurements of fair value with respect to financial assets and liabilities, during the periods presented, other than those assets and liabilities that are measured at fair value on a recurring basis. Other than the warrants issued in connection with the private placement transaction which closed on September 29, 2016, the Company had no assets or liabilities classified as Level 3 as of September 30, 2017 and December 31, 2016. Transfers are calculated on values as of the transfer date. There were no transfers between Levels 1, 2 and 3 during the nine months ended September 30, 2017 and twelve months ended December 31, 2016. The fair value of the warrants is considered a Level 3 valuation and was determined using a Monte Carlo simulation model. This model incorporated several assumptions at each valuation date including: the price of the Company’s common stock on the date of valuation, the historical volatility of the price of the Company’s common stock, the remaining contractual term of the warrant and estimates of the probability of a fundamental transaction occurring (See Note 6 for further discussion of the private placement). The Company’s financial instruments as of September 30, 2017 consisted primarily of cash and cash equivalents, marketable securities and warrant liability. The Company’s financial instruments as of December 31, 2016 consisted primarily of cash and cash equivalents and warrant liability. As of September 30, 2017, and December 31, 2016, the Company’s financial assets recognized at fair value consisted of the following: Description Total Quoted prices in active markets (Level 1) Significant other observable (Level 2) Significant unobservable inputs (Level 3) (in thousands) September 30, 2017 Assets: Cash Equivalents Money market funds $ 4,603 $ 4,603 $ — $ — Marketable securities: Asset-backed securities 900 — 900 — Corporate notes 921 — 921 — Total $ 6,424 $ 4,603 $ 1,821 $ — Liabilities: Warrant liability $ 13,871 $ — $ — $ 13,871 December 31, 2016 Assets: Money market funds $ 30,318 $ 30,318 $ — $ — Liabilities: Warrant liability $ 13,198 $ — $ — $ 13,198 The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs: As of September 30, 2017 (in thousands) Beginning balance, December 31, 2016 $ 13,198 Change in fair value of warrant liability 673 Ending balance $ 13,871
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid securities with original maturities of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents are comprised of funds in money market accounts.
Marketable Securities	Marketable Securities The Company classifies marketable securities with a remaining maturity when purchased of greater than three months as available for sale. The Company considers all available for sale securities, including those with maturity dates beyond 12 months, as available to support current operational liquidity needs and therefore classifies all securities including those with maturity dates beyond 90 days at the date of purchase as current assets within the consolidated balance sheets. Available for sale securities are maintained by the Company’s investment managers and may consist of commercial paper, high-grade corporate notes, U.S. Treasury securities, U.S. government agency securities, and certificates of deposit. Available for sale securities are carried at fair value with the unrealized gains and losses included in other comprehensive income (loss) as a component of stockholders’ equity (deficit) until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expense over the life of the instrument. Realized gains and losses are determined using the specific identification method and are included in other income (expense). If any adjustment to fair value reflects a decline in value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other-than-temporary” and, if so, marks the investment to market through a charge to the Company’s consolidated statement of operations and comprehensive loss. The following table summarizes the available for sale securities held at September 30, 2017: Description Amortized Unrealized Gains Unrealized Losses Fair (in thousands) Asset-backed securities $ 900 $ — $ — $ 900 Corporate notes 921 — — 921 Total $ 1,821 $ — $ — $ 1,821 The Company did not hold any available for sale securities prior to the first quarter of 2017. The amortized cost of available for sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At September 30, 2017, the balance in the Company’s accumulated other comprehensive loss was composed solely of activity related to the Company’s available for sale marketable securities. There were no sales of available for sale securities during the quarter ended September 30, 2017. The aggregate fair value of available for sale securities held by the Company for less than twelve months as of September 30, 2017 was $1.8 million. The Company determined that there was no material change in the credit risk of any of its investments. As a result, the Company determined it did not hold any investments with any other-than-temporary impairment as of September 30, 2017. The weighted average maturity of the Company’s portfolio was approximately one month at September 30, 2017.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock options and restricted stock based on their grant date fair value and recognizes compensation expense on a straight-line basis over their vesting period. The Company estimates the fair value of stock options as of the date of grant using the Black-Scholes option pricing model, with the exception of stock options that include a market condition, and restricted stock based on the fair value of the underlying common stock as of the date of grant or the value of the services provided, whichever is more readily determinable. The Company, in conjunction with adoption of ASU 2016-09- Stock Compensation: Improvements to Employee Share-Based Payment Accounting For stock option grants with vesting triggered by the achievement of performance-based milestones, the expense is recorded over the remaining service period after the point when the achievement of the milestone is probable or the performance condition has been achieved. For stock option grants with both performance-based milestones and market conditions, expense is recorded over the derived service period after the point when the achievement of the performance-based milestone is probable or the performance condition has been achieved. For stock option grants with market conditions, the expense is calculated using the Monte Carlo model based on the grant date fair value of the option and is recorded on a straight line basis over the requisite service period, which represents the derived service period and accelerated when the market condition is satisfied. The Company did not issue awards with market conditions during the nine months ended September 30, 2017. The Company accounts for stock options and restricted stock awards to non-employees using the fair value approach. Stock options and restricted stock awards to non-employees are subject to periodic revaluation over their vesting terms.
Warrant Accounting	Warrant Accounting As noted in Note 6, Capital Stock, the Company classifies a warrant to purchase shares of its common stock as a liability on its consolidated balance sheet if the warrant is a free-standing financial instrument that may require the Company to transfer consideration upon exercise. Each warrant of this type is initially recorded at fair value on date of grant using the Monte Carlo simulation model and net of issuance costs, and is subsequently re-measured to fair value at each subsequent balance sheet date. Changes in fair value of the warrant are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. The Company will continue to adjust the liability for changes in fair value until the earlier of the exercise or expiration of the warrant.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The standard requires restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods shown on the statement of cash flows. The new standard is effective for the Company on January 1, 2018 using a retrospective transition method to each period presented. Early adoption is permitted. We are currently evaluating the timing of our adoption and the expected impact that this standard could have on our consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Shared-Based Payment Accounting. This standard provides guidance on accounting for employee share-based payments. This guidance addresses several aspects of the accounting for share-based payment award transactions, including: (a) income tax consequences; (b) classification of awards as either equity or liabilities; and (c) classification on the statement of cash flows. This standard will be effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company has concluded that this guidance has no material impact on the presentation of its results of operations, financial position and disclosures. In February 2016, the FASB issued ASU No. 2016-02- Leases (Topic 842). This standard requires companies to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leased assets. ASU 2016-02 will be effective for the Company in the first quarter of 2019, with early adoption permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-02 will have on the Company’s consolidated financial statements and related disclosures. In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. This standard provides guidance that requires management to assess an entity’s ability to continue as a going concern every reporting period, and provide certain disclosures if management has substantial doubt about the entity’s ability to operate as a going concern, or an express statement if not, by incorporating and expanding upon certain principles that are currently in U.S. auditing standards. This guidance is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. The Company adopted this guidance in the fourth quarter of 2016 and made the relevant disclosures in the consolidated financial statements and related footnotes. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In July 2015, the FASB issued a one-year deferral of the effective date of the new revenue recognition standard. The new guidance will be effective for the Company’s first quarter of fiscal year 2018 and early application for fiscal year 2017 is permitted. The Company’s adoption of this guidance is not expected to have a material impact on the consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting. This standard provides guidance on changes to the terms or conditions of a share based payment award that requires an entity to apply modification accounting. The guidance is effective for annual periods beginning after December 15, 2017, and for interim periods and annual periods thereafter. The Company is currently evaluating the impact that the adoption of this guidance will have on the Company’s consolidated 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. This update addresses the complexity of accounting for certain financial instruments with down round features. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company has concluded that this guidance has no impact on the presentation of its results of operations, financial position and disclosures.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	As of September 30, 2017, and December 31, 2016, the Company’s financial assets recognized at fair value consisted of the following: Description Total Quoted prices in active markets (Level 1) Significant other observable (Level 2) Significant unobservable inputs (Level 3) (in thousands) September 30, 2017 Assets: Cash Equivalents Money market funds $ 4,603 $ 4,603 $ — $ — Marketable securities: Asset-backed securities 900 — 900 — Corporate notes 921 — 921 — Total $ 6,424 $ 4,603 $ 1,821 $ — Liabilities: Warrant liability $ 13,871 $ — $ — $ 13,871 December 31, 2016 Assets: Money market funds $ 30,318 $ 30,318 $ — $ — Liabilities: Warrant liability $ 13,198 $ — $ — $ 13,198
Schedule of Reconciliation of Liabilities Measured at Fair Value	The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs: As of September 30, 2017 (in thousands) Beginning balance, December 31, 2016 $ 13,198 Change in fair value of warrant liability 673 Ending balance $ 13,871
Summary of Available for Sale Securities	The following table summarizes the available for sale securities held at September 30, 2017: Description Amortized Unrealized Gains Unrealized Losses Fair (in thousands) Asset-backed securities $ 900 $ — $ — $ 900 Corporate notes 921 — — 921 Total $ 1,821 $ — $ — $ 1,821

Loss Per Common Share (Tables)

Loss Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Loss Per Common Share	For the three and nine months ended September 30, 2017 and 2016, there was no dilution attributed to the weighted-average shares outstanding in the calculation of diluted loss per share. Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (In thousands, except share and per share data) Numerator: Net loss $ (5,995 ) $ (9,315 ) $ (19,618 ) $ (25,271 ) Net loss attributable to Series A Preferred Stock (a) (915 ) (81 ) (3,238 ) (74 ) Loss attributable to common stockholders—basic and diluted $ (5,080 ) $ (9,234 ) $ (16,380 ) $ (25,197 ) Denominator: Weighted-average number of common shares used in loss per share—basic and diluted 22,552,341 13,297,546 22,219,666 13,279,833 Loss per share—basic and diluted $ (0.23 ) $ (0.70 ) $ (0.74 ) $ (1.90 ) (a) The Series A Preferred Stock participates in income and losses.
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding, as they would be anti-dilutive (in common stock equivalent shares): For the Three and Nine Months Ended September 30, 2017 2016 Unvested restricted stock and options to purchase common stock 2,194,630 882,887 Series A preferred stock unconverted 3,826,920 — Warrants exercisable into common stock 13,633,070 13,633,070

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following: September 30, December 31, 2017 2016 (in thousands) Office equipment $ 279 $ 266 Laboratory equipment 4,511 4,443 Leasehold improvements 7,712 7,683 Construction in progress 779 759 Software 96 96 Total property and equipment 13,377 13,247 Less: accumulated depreciation (10,563 ) (9,387 ) Property and equipment, net $ 2,814 $ 3,860

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity Under the 2012 and 2013 Plans	Stock option activity under the Company’s 2012 Equity Incentive Plan (the “2012 Plan”) and 2013 Equity Incentive Plan (the “2013 Plan”) for the nine months ended September 30, 2017 is summarized as follows: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2016 1,577,016 $ 5.95 Granted 860,000 1.72 Exercised (7,497 ) 0.76 Cancelled (234,889 ) 4.27 Outstanding at September 30, 2017 2,194,630 $ 4.48 8.3 $ 362 Vested and expected to vest at September 30, 2017 2,027,533 $ 4.60 8.3 $ 327 Exercisable at September 30, 2017 934,872 $ 5.91 7.6 $ 120
Schedule of Restricted Stock Awards Under the 2012 and 2013 Plans	Restricted stock awards under the 2012 Plan and 2013 Plan for the nine months ended September 30, 2017 are summarized as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2016 1,889 $ 0.83 Vesting of restricted stock (1,889 ) 0.83 Unvested at September 30, 2017 — $ —
Summary of Stock-Based Compensation for all Options Granted and Restricted Stock Awards	The allocation of stock-based compensation for all options granted and restricted stock awards is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands) (in thousands) Research and development $ 86 $ 126 $ 326 $ 364 General and administrative 283 309 907 716 Total stock-based compensation expense $ 369 $ 435 $ 1,233 $ 1,080
Summary of Stock-Based Compensation by Award	Stock-based compensation by award type is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands) (in thousands) Stock options $ 369 $ 434 $ 1,233 $ 1,078 Restricted stock — 1 — 2 Total stock-based compensation expense $ 369 $ 435 $ 1,233 $ 1,080
Summary of Weighted-Average Assumptions Used in the Black-Scholes Option Pricing Model to Determine the Fair Value of the Employee Stock Option Grants	The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Risk-free interest rate 1.95 % 1.36 % 2.03 % 1.39 % Expected volatility 60.0 % 85.2 % 63.1 % 59.7 % Expected term (in years) 6.08 6.08 6.08 6.08 Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 %
Summary of Weighted-Average Assumptions Used in the Black-Scholes Option Pricing Model to Determine the Fair Value of the Non-Employee Stock Option Grants	The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the non-employee stock option grants were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Risk-free interest rate 1.35 % 1.53 % 1.28 % 1.59 % Expected volatility 59.7 % 63.2 % 63.0 % 63.6 % Expected term (in years) 6.08 6.97 6.08 7.00 Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 %

Equipment Loan Payable (Tables)

Equipment Loan Payable (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Outstanding Borrowing Obligations	As of September 30, 2017 and December 31, 2016, the Company had the following outstanding borrowing obligations: September 30, December 31, 2017 2016 (in thousands) Silicon Valley Bank Equipment Loan Payable $ 324 $ 761 Less: current portion (324 ) (583 ) Long-term debt, net $ — $ 178
Schedule of Maturities of Debt	The scheduled maturities of the Company’s debt are as follows: September 30, 2017 (in thousands) December 31, 2017 $ 146 May 31, 2018 178 Total $ 324

Nature of Business - Additional

Nature of Business - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 29, 2016	May 13, 2011	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Nature Of Business And Basis Of Presentation [Line Items]
Proceeds from issuance of issuance of common stock, preferred stock and warrants, net of issuance costs	$ 27,600			$ 27,674
Accumulated deficit			$ (201,391)		$ (181,773)
Cash and cash equivalents and marketable securities			$ 12,600
ProChon [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Business acquisition date			May 13, 2011
Consideration paid to acquisition		$ 2,200

Summary of Significant Accoun24

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Transfers between Levels 1, 2 and 3	$ 0	$ 0
Sale of available for sale securities	0
Aggregate fair value of available for sale securities held for less than twelve months	1,800,000
Significant Unobservable Inputs (Level 3) [Member]
Summary Of Significant Accounting Policies [Line Items]
Assets, fair value disclosure, recurring	0	0
Liabilities, fair value disclosure, recurring	$ 0	$ 0

Summary of Significant Accoun25

Summary of Significant Accounting Policies - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Cash Equivalents
Assets, fair value	$ 6,424
Marketable securities:
Assets, fair value	6,424
Assets, fair value	6,424
Warrant Liability [Member]
Liabilities:
Liabilities, fair value	13,871	$ 13,198
Money Market Funds [Member]
Cash Equivalents
Assets, fair value	4,603	30,318
Marketable securities:
Assets, fair value	4,603	30,318
Assets, fair value	4,603	30,318
Asset Backed Securities [Member]
Cash Equivalents
Assets, fair value	900
Marketable securities:
Assets, fair value	900
Assets, fair value	900
Corporate Notes [Member]
Cash Equivalents
Assets, fair value	921
Marketable securities:
Assets, fair value	921
Assets, fair value	921
Quoted Prices in Active Markets (Level 1) [Member]
Cash Equivalents
Assets, fair value	4,603
Marketable securities:
Assets, fair value	4,603
Assets, fair value	4,603
Quoted Prices in Active Markets (Level 1) [Member] | Money Market Funds [Member]
Cash Equivalents
Assets, fair value	4,603	30,318
Marketable securities:
Assets, fair value	4,603	30,318
Assets, fair value	4,603	30,318
Significant Other Observable Inputs (Level 2) [Member]
Cash Equivalents
Assets, fair value	1,821
Marketable securities:
Assets, fair value	1,821
Assets, fair value	1,821
Significant Other Observable Inputs (Level 2) [Member] | Asset Backed Securities [Member]
Cash Equivalents
Assets, fair value	900
Marketable securities:
Assets, fair value	900
Assets, fair value	900
Significant Other Observable Inputs (Level 2) [Member] | Corporate Notes [Member]
Cash Equivalents
Assets, fair value	921
Marketable securities:
Assets, fair value	921
Assets, fair value	921
Significant Unobservable Inputs (Level 3) [Member] | Warrant Liability [Member]
Liabilities:
Liabilities, fair value	$ 13,871	$ 13,198

Summary of Significant Accoun26

Summary of Significant Accounting Policies - Schedule of Reconciliation of Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value of warrant liability	$ 269	$ (539)	$ 673	$ (539)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance			13,198
Change in fair value of warrant liability			673
Ending balance	$ 13,871		$ 13,871

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Summary of Available for Sale Securities (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,821
Unrealized Gains	0
Unrealized Losses	0
Fair Value	1,821
Asset Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	900
Unrealized Gains	0
Unrealized Losses	0
Fair Value	900
Corporate Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	921
Unrealized Gains	0
Unrealized Losses	0
Fair Value	$ 921

Loss Per Common Share - Schedul

Loss Per Common Share - Schedule of Basic and Diluted Loss Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net loss	$ (5,995)	$ (9,315)	$ (19,618)	$ (25,271)
Net loss attributable to Series A Preferred Stock	(915)	(81)	(3,238)	(74)
Loss attributable to common stockholders-basic and diluted	$ (5,080)	$ (9,234)	$ (16,380)	$ (25,197)
Denominator:
Weighted-average number of common shares used in loss per share-basic and diluted	22,552,341	13,297,546	22,219,666	13,279,833
Loss per share-basic and diluted	$ (0.23)	$ (0.70)	$ (0.74)	$ (1.90)

Loss Per Common Share - Sched29

Loss Per Common Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Series A Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	3,826,920		3,826,920
Unvested Restricted Stock and Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	2,194,630	882,887	2,194,630	882,887
Warrants Exercisable into Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	13,633,070	13,633,070	13,633,070	13,633,070

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 13,377	$ 13,247
Less: accumulated depreciation	(10,563)	(9,387)
Property and equipment, net	2,814	3,860
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	279	266
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	4,511	4,443
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	7,712	7,683
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	779	759
Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 96	$ 96

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 389	$ 404	$ 1,178	$ 1,267

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended
	Feb. 28, 2017USD ($)	Sep. 30, 2015	Jun. 30, 2012USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)Options	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Loss Contingencies [Line Items]
Rent expense under operating lease agreements				$ 248,000	$ 248,000	$ 743,000	$ 742,000
Research and development expense				3,488,000	$ 4,880,000	12,200,000	$ 16,260,000
Waltham [Member]
Loss Contingencies [Line Items]
Tenant improvement allowance for future rental payments						$ 500,000
Lease renewal date						Jan. 1, 2018
Hydrogel License Agreement [Member]
Loss Contingencies [Line Items]
Research and development expense						$ 3,200,000
Amount paid during period for amending the agreement				3,000,000		3,000,000
Tissue Regeneration License Agreement [Member]
Loss Contingencies [Line Items]
Research and development expense						800,000
Amount paid during period for amending the agreement				300,000		$ 300,000
Percentage of royalty offsetting						50.00%
Maximum [Member] | Waltham [Member]
Loss Contingencies [Line Items]
Construction allowances to total cost of tenant improvements						$ 3,184,000
Tenant improvement allowance				900,000		900,000
Maximum [Member] | Lexington [Member]
Loss Contingencies [Line Items]
Construction allowances to total cost of tenant improvements						996,000
Minimum [Member] | Tissue Regeneration License Agreement [Member]
Loss Contingencies [Line Items]
Non-refundable royalty fee						10,000
Tissue Processor Sub License Agreement [Member]
Loss Contingencies [Line Items]
Research and development expense						1,000,000
Reimbursement for development cost			$ 300,000
Potential milestone payments				10,200,000		10,200,000
Additional non-refundable royalty fee						$ 30,000
Additional non-refundable royalty fee payment description						2016 through 2019
Tissue Processor Sub License Agreement [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Non-refundable royalty fee						$ 20,000
Engineering Agreement [Member]
Loss Contingencies [Line Items]
Amount paid to suppliers						600,000		$ 200,000
Additional payments due				0		0
Collagen Supply Agreement [Member]
Loss Contingencies [Line Items]
Amount paid during period for amending the agreement				70,000		$ 70,000
Minimum amount of material and/or services	$ 100,000
Initial term of the agreement		3 years
Supplier agreement description						The initial term of the agreement is three years and will automatically renew from year to year thereafter unless otherwise terminated with at least 180 days’ notice by either party.
Amount agreed for amending minimum annual order	$ 100,000
Amount paid during period for amending the agreement						$ 30,000
OCS Agreement [Member]
Loss Contingencies [Line Items]
Accrued and received grants, aggregate				$ 1,100,000		$ 1,100,000
OCS Agreement [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Royalties payment, rate						5.00%
Royalty payment percentage as percentage of grant received						300.00%
OCS Agreement [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Royalties payment, rate						3.00%
Royalty payment percentage as percentage of grant received						100.00%
Massachusetts [Member] | Waltham [Member]
Loss Contingencies [Line Items]
Lease expiration period						2,023
Amended lease termination date						Jan. 31, 2018
Lease termination date						Dec. 31, 2024
Additional operating lease term						5 years
Number of additional renewal terms | Options						1
Massachusetts [Member] | Lexington [Member]
Loss Contingencies [Line Items]
Lease expiration period						2,023

Capital Stock - Additional Info

Capital Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Sep. 29, 2016	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Class of Stock [Line Items]
Proceeds from issuance of issuance of common stock, preferred stock and warrants, net of issuance costs	$ 27,600			$ 27,674
Warrant expense		$ 3,056		$ 3,056
Minimum threshold percentage of beneficial common stock interest	4.99%
Maximum threshold percentage of beneficial common stock interest on holder's discretion	9.99%
Convertible preferred stock, terms of conversion			The Series A Preferred Stock shall not be converted if, after giving effect to the conversion, the holder and its affiliated persons would own beneficially more than 4.99% of our common stock (subject to adjustment up to 9.99% solely at the holder’s discretion upon 61 days’ prior notice to us or, solely as to a holder, if such limitation is waived by such holder upon execution of the private placement agreement).
Private Placement [Member]
Class of Stock [Line Items]
Gross proceeds from issuance of common stock, preferred stock and warrants	$ 30,000
Common stock price per share	$ 2.25
Conversion of preferred stock in to common stock, preferred stock converted	10,737,275		444.44
Class of Warrants or right to purchase common stock	13,333,334
Class of Warrants or right to purchase common stock, exercise price	$ 2.25		$ 2.25
Warrants granted to placement agent	133,333
Proceeds from issuance of issuance of common stock, preferred stock and warrants, net of issuance costs	$ 27,600
Warrants granted to placement agent, exercise price	$ 2.25
Minimum percentage of outstanding common stock			50.00%
Warrants expiry period			5 years
Warrants exercisable period			6 months
Fair value of warrants			$ 30,700
Excess fair value of warrant liability			400
Warrant expense			$ 3,100
Preferred stock par value			$ 0.01
Private Placement [Member] | Common Stock [Member]
Class of Stock [Line Items]
Number of shares issued	2,596,059
Private Placement [Member] | Series A Preferred Stock [Member]
Class of Stock [Line Items]
Number of shares issued	24,158.8693		24,158.8693
Conversion of preferred stock in to common stock, preferred stock converted			10,737,275
Convertible preferred stock, shares outstanding			8,610.5701
Private Placement [Member] | Series A Preferred Stock [Member] | Common Stock [Member]
Class of Stock [Line Items]
Conversion of preferred stock in to common stock, preferred stock converted			3,826,920
Private Placement [Member] | Members of Board of Directors [Member]
Class of Stock [Line Items]
Class of Warrants or right to purchase common stock			1,422,221
Class of Warrants or right to purchase common stock, exercise price			$ 2.25
Private Placement [Member] | Members of Board of Directors [Member] | Common Stock [Member]
Class of Stock [Line Items]
Number of shares issued			283,046
Private Placement [Member] | Members of Board of Directors [Member] | Series A Preferred Stock [Member]
Class of Stock [Line Items]
Number of shares issued			2,563.1439

Warrants - Additional Informati

Warrants - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands

Sep. 30, 2017

Dec. 31, 2016

Dec. 21, 2015

Jul. 09, 2014

Jul. 20, 2012

Dec. 31, 2014

Jul. 31, 2014

Jul. 31, 2012

Sep. 30, 2017

Sep. 30, 2015

Sep. 30, 2016

Mar. 31, 2015

Investor Warrants [Member]

Class of Warrant or Right [Line Items]

Class of Warrants or right to purchase common stock

13,333,334

Class of Warrants or right to purchase common stock, exercise price

$ 2.25

Warrants exercisable period

6 months

Warrants expiry period

5 years

Warrant expense

$ 2.28

$ 2.28

Placement Agent Warrant [Member]

Class of Warrant or Right [Line Items]

Class of Warrants or right to purchase common stock

133,333

Class of Warrants or right to purchase common stock, exercise price

$ 2.25

Warrants expiry period

5 years

Warrant expense

$ 2.28

$ 2.28

Consulting Agreement Warrant [Member]

Class of Warrant or Right [Line Items]

Class of Warrants or right to purchase common stock

7,398

Class of Warrants or right to purchase common stock, exercise price

$ 9.75

Warrants exercisable period

24 months

Warrants expiry period

10 years

Warrants, forfeiture

(3,699)

Warrants vested and exercisable

3,699

3,699

Warrants, percentage of forfeiture

50.00%

Affiliates Of Advisor Warrant [Member]

Class of Warrant or Right [Line Items]

Class of Warrants or right to purchase common stock

156,138

156,138

161,977

156,138

Class of Warrants or right to purchase common stock, exercise price

$ 0.01

$ 0.01

$ 0.01

$ 0.01

Warrants expiry period

10 years

Surrender of warrant to satisfy related liability

5,839

Fair value of warrants

$ 117

Fair value of the warrants, risk free interest rate

0.22%

Fair value of the warrants, implied volatility

99.00%

Fair value of the warrants, expected term to liquidity

1 year 8 months 12 days

Silicon Valley Bank [Member]

Class of Warrant or Right [Line Items]

Class of Warrants or right to purchase common stock

6,566

Class of Warrants or right to purchase common stock, exercise price

$ 7.99

Warrants expiry period

10 years

Fair value of warrants

$ 51

Fair value of the warrants, risk free interest rate

2.58%

Fair value of the warrants, implied volatility

87.00%

Fair value of the warrants, expected term to liquidity

10 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity Under the 2012 and 2013 Plans (Detail) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options, Outstanding Beginning Balance | shares	1,577,016
Number of Options, Granted | shares	860,000
Number of Options, Exercised | shares	(7,497)
Number of Options, Cancelled | shares	(234,889)
Number of Options, Outstanding Ending Balance | shares	2,194,630
Number of Options, Vested and expected to vest outstanding | shares	2,027,533
Number of Options, Exercisable | shares	934,872
Weighted Average Exercise Price, Outstanding Beginning Balance | $ / shares	$ 5.95
Weighted Average Exercise Price, Granted | $ / shares	1.72
Weighted Average Exercise Price, Exercised | $ / shares	0.76
Weighted Average Exercise Price, Cancelled | $ / shares	4.27
Weighted Average Exercise Price, Outstanding Ending Balance | $ / shares	4.48
Weighted Average Exercise Price, Vested and expected to vest outstanding | $ / shares	4.60
Weighted Average Exercise Price, Exercisable | $ / shares	$ 5.91
Weighted Average Remaining Contractual Term, Outstanding	8 years 3 months 19 days
Weighted Average Remaining Contractual Term, Vested and expected to vest outstanding	8 years 3 months 19 days
Weighted Average Remaining Contractual Term, Exercisable	7 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding | $	$ 362
Aggregate Intrinsic Value, Vested and expected to vest outstanding | $	327
Aggregate Intrinsic Value, Exercisable | $	$ 120

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to outstanding options	$ 1,700		$ 1,700
Weighted average grant date fair value of vested options			$ 3.96
Weighted average grant date fair value of options outstanding	$ 2.76		2.76
Weighted average grant date fair value per share of employee option granted	$ 1.14	$ 2.47	$ 1.01	$ 1.40
Stock-based compensation expense	$ 369	$ 435	$ 1,233	$ 1,080
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, recognition period			1 year 9 months 22 days
Stock-based compensation expense	$ 369	$ 434	$ 1,233	$ 1,078

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Restricted Stock Awards Under the 2012 and 2013 Plans (Detail) - Restricted Stock [Member]	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Unvested beginning balance | shares	1,889
Vesting of restricted stock | shares	(1,889)
Weighted-average grant date fair value, Unvested beginning balance | $ / shares	$ 0.83
Vesting of restricted stock | $ / shares	$ 0.83

Stock-Based Compensation - Su38

Stock-Based Compensation - Summary of Stock-Based Compensation for all Options Granted and Restricted Stock Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 369	$ 435	$ 1,233	$ 1,080
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	86	126	326	364
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 283	$ 309	$ 907	$ 716

Stock-Based Compensation - Su39

Stock-Based Compensation - Summary of Stock-Based Compensation by Award (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 369	$ 435	$ 1,233	$ 1,080
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 369	434	$ 1,233	1,078
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense		$ 1		$ 2

Stock-Based Compensation - Su40

Stock-Based Compensation - Summary of Weighted-Average Assumptions Used in the Black-Scholes Option Pricing Model to Determine the Fair Value of the Employee Stock Option Grants (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate	1.95%	1.36%	2.03%	1.39%
Expected volatility	60.00%	85.20%	63.10%	59.70%
Expected term (in years)	6 years 29 days	6 years 29 days	6 years 29 days	6 years 29 days
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Stock-Based Compensation - Su41

Stock-Based Compensation - Summary of Weighted-Average Assumptions Used in the Black-Scholes Option Pricing Model to Determine the Fair Value of the Non-Employee Stock Option Grants (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Goods and Nonemployee Services Transaction [Abstract]
Risk-free interest rate	1.35%	1.53%	1.28%	1.59%
Expected volatility	59.70%	63.20%	63.00%	63.60%
Expected term (in years)	6 years 29 days	6 years 11 months 19 days	6 years 29 days	7 years
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Equipment Loan Payable - Schedu

Equipment Loan Payable - Schedule of Outstanding Borrowing Obligations (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total debt	$ 324
Less: current portion	(324)	$ (583)
Long-term debt, net		178
Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Total debt	$ 324	$ 761

Equipment Loan Payable - Additi

Equipment Loan Payable - Additional Information (Detail) - Silicon Valley Bank [Member]	1 Months Ended
	Jul. 31, 2014USD ($)$ / sharesshares
Class of Warrant or Right [Line Items]
Amount of loan to purchase equipment | $	$ 1,800,000
Line of credit facility, interest rate, stated percentage	3.25%
Bank loan and security agreement, repayment period	36 months
Net exercise of warrants, shares | shares	6,566
Net exercise of warrants, exercise price per share | $ / shares	$ 7.99
Prime Rate [Member]
Class of Warrant or Right [Line Items]
Amount of loan bears interest basis spread on variable rate	2.75%

Equipment Loan Payable - Sche44

Equipment Loan Payable - Schedule of Maturities of Debt (Detail) $ in Thousands	Sep. 30, 2017USD ($)
Long-term Debt, Fiscal Year Maturity [Abstract]
December 31, 2017	$ 146
May 31, 2018	178
Total debt	$ 324

Related Parties - Additional In

Related Parties - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Jun. 30, 2012
Intrexon [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration Agreement cancellation notification	90 days
Collaboration Agreement cancellation with material breach that cannot be remedied	60 days
Accrued expenses due to related party	$ 3,000,000		$ 3,000,000
Intrexon [Member] | Commercialization Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Commercialization milestones obligation	12,000,000
Intrexon [Member] | Sales Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Sales milestones	$ 22,500,000
Intrexon [Member] | Research and Development [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of reimbursement expenses	50.00%
Percentage of reimbursement expenses subject to acceptance	50.00%
Research and development expense from transaction with Intrexon	$ 0	$ 2,300,000
Purpose, Co. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement for development cost, amount				$ 300,000
Reimbursement for development cost, paid	$ 100,000	$ 100,000