Avexis (AVXS) 10-K 16 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Mar. 14, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	AveXis, Inc.
Entity Central Index Key	1,652,923
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 572,777,155
Entity Common Stock, Shares Outstanding		27,739,724
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 240,429,839	$ 62,251,860
Prepaid expenses and other current assets	4,750,469	909,629
Total current assets	245,180,308	63,161,489
Property and equipment, net	24,200,582	235,590
Other long-term assets	1,194,541	1,687,212
Total assets	270,575,431	65,084,291
Current liabilities:
Accounts payable	3,197,274	359,787
Accrued expenses	16,794,003	2,437,017
Accrued indemnification obligation	4,452,500	4,080,500
Total current liabilities	24,443,777	6,877,304
Total liabilities	24,443,777	6,877,304
Redeemable common stock; par value $0.0001 per share, no shares issued and outstanding at December 31, 2016; 456,043 shares issued and outstanding at December 31, 2015		1,032,909
Stockholders' equity (deficit):
Common stock; par value $0.0001 per share, 100,000,000 shares authorized, 27,700,054 shares issued and outstanding at December 31, 2016; 22,080,000 shares authorized, 6,817,093 shares issued and outstanding at December 31, 2015	2,770	682
Additional paid-in capital	387,691,208	115,723,046
Accumulated deficit	(141,562,324)	(58,550,520)
Total stockholder's equity (deficit)	246,131,654	57,174,078
Total liabilities, redeemable common stock and stockholders' equity (deficit)	$ 270,575,431	65,084,291
Class D Preferred Stock
Stockholders' equity (deficit):
Preferred stock		309
Total stockholder's equity (deficit)		309
Class C Preferred Stock
Stockholders' equity (deficit):
Preferred stock		237
Total stockholder's equity (deficit)		237
Class B-1 Preferred Stock
Stockholders' equity (deficit):
Preferred stock		324
Total stockholder's equity (deficit)		$ 324

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Redeemable common stock
Redeemable common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Redeemable common stock, shares issued (in shares)	0	456,043
Redeemable common stock, shares outstanding (in shares)	0	456,043
Common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	22,080,000
Common stock, shares issued (in shares)	27,700,054	6,817,093
Common stock, shares outstanding (in shares)	27,700,054	6,817,093
Class D Preferred Stock
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)		3,105,000
Preferred stock, shares issued (in shares)	0	3,093,092
Preferred stock, shares outstanding (in shares)	0	3,093,092
Class C Preferred Stock
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)		2,365,020
Preferred stock, shares issued (in shares)	0	2,365,020
Preferred stock, shares outstanding (in shares)	0	2,365,020
Preferred stock, aggregate liquidation preference (in dollars)		$ 9,372,112
Class B-1 Preferred Stock
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)		3,278,938
Preferred stock, shares issued (in shares)	0	3,237,528
Preferred stock, shares outstanding (in shares)	0	3,237,528
Preferred stock, aggregate liquidation preference (in dollars)		$ 8,000,003

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating expenses:
General and administrative	$ 24,522,902	$ 11,079,512	$ 1,869,899
Research and development	58,891,667	27,493,460	13,550,422
Total operating expenses	83,414,569	38,572,972	15,420,321
Loss from operations	(83,414,569)	(38,572,972)	(15,420,321)
Other income		84,558
Interest income (expense)	402,765	14,570	(131,527)
Loss from continuing operations, before income taxes	(83,011,804)	(38,473,844)	(15,551,848)
Loss from continuing operations	(83,011,804)	(38,473,844)	(15,551,848)
Loss from discontinued operations, net of tax			(8,729)
Loss from sale of discontinued operations, net of tax			(145,199)
Net loss	(83,011,804)	(38,473,844)	(15,705,776)
Comprehensive loss	$ (83,011,804)	$ (38,473,844)	$ (15,705,776)
Basic and diluted net loss per common share from continuing operations (Note 11)	$ (3.67)	$ (5.43)	$ (2.37)
Basic and diluted net loss per common share from discontinued operations (Note 11)			(0.02)
Basic and diluted net loss per common share (Note 11) (in dollars per share)	$ (3.67)	$ (5.43)	$ (2.39)
Weighted-average basic and diluted common shares outstanding (in shares)	22,647,583	7,087,618	6,916,404

Consolidated Statements of Chan

Consolidated Statements of Changes in Redeemable Common Stock and Stockholders' Equity (Deficit) - USD ($)	Redeemable Common StockIPO	Redeemable Common Stock	Class D Preferred StockIPO	Class D Preferred Stock	Class C Preferred StockIPO	Class C Preferred StockDeerfield Convertible Note	Class C Preferred Stock	Class B-1 Preferred StockIPO	Class B-1 Preferred StockClass B Note	Class B-1 Preferred Stock	Common StockIPO	Common StockFollow-On Offering	Common Stock	Additional Paid-in CapitalIPO	Additional Paid-in CapitalFollow-On Offering	Additional Paid-in CapitalClass B Note	Additional Paid-in CapitalDeerfield Convertible Note	Additional Paid-in Capital	Accumulated Deficit	IPO	Follow-On Offering	Class B Note	Deerfield Convertible Note	Total
Balance at the beginning of the period at Dec. 31, 2013		$ 345,447
Balance at the beginning of the period (in shares) at Dec. 31, 2013		331,053
Increase (Decrease) in Redeemable Common Stock
Issuance of redeemable common stock at fair value		$ 214,298
Issuance of redeemable common stock at fair value (in shares)		86,725
Shares conversion amount													$ (122)
Shares conversion (in shares)													(1,214,077)
Balance at the end of the period at Dec. 31, 2014		$ 559,745
Balance at the end of the period (in shares) at Dec. 31, 2014		417,778
Balance at the beginning of the period at Dec. 31, 2013													$ 706					$ 2,727,038	$ (4,370,843)					$ (1,643,099)
Balance at the beginning of the period (in shares) at Dec. 31, 2013													7,061,173
Increase (Decrease) in Stockholders' Equity (Deficit)
Stock-based compensation - restricted stock																		5,749,774
Stock based compensation-restricted stock													$ 59											5,749,833
Stock based compensation-restricted stock (in shares)													583,597
Stock-based compensation - stock options																		416,624						416,624
Stock-based compensation - stock warrants																		243,863						243,863
Stock-based compensation - shares exchange																		193,549						193,549
Stock-based compensation - share grants																		594,088						594,088
Shares conversion amount													$ (122)
Share exchanges										$ 122
Share exchanges (in shares)										1,214,077
Issuance of Class B-1 preferred stock and B-2 warrants										$ 81								1,999,919						2,000,000
Conversion of convertible debt						$ 13			$ 20													$ 612,835	$ 503,424	1,000,000
Conversion of convertible debt (in shares)						126,991			202,345
Conversion of convertible debt																$ 612,815	$ 503,411
Issuance of Class C Milestone Shares							$ 113											4,499,921						4,500,034
Issuance of stock (in shares)							1,135,084			809,385
Issuance of common stock to vendor													$ 4					102,296						102,300
Issuance of common stock to vendor (in shares)													41,400
Net loss																			(15,705,776)					(15,705,776)
Balance at the end of the period at Dec. 31, 2014							$ 126			$ 223			$ 647					17,643,298	(20,076,619)					(2,432,325)
Balance at the end of the period (in shares) at Dec. 31, 2014							1,262,075			2,225,807			6,472,093
Increase (Decrease) in Redeemable Common Stock
Issuance of redeemable common stock at fair value		$ 473,164
Issuance of redeemable common stock at fair value (in shares)		38,265
Balance at the end of the period at Dec. 31, 2015		$ 1,032,909																						$ 1,032,909
Balance at the end of the period (in shares) at Dec. 31, 2015		456,043																						456,043
Increase (Decrease) in Stockholders' Equity (Deficit)
Stock-based compensation - restricted stock																		19,322,275						$ 19,322,275
Stock-based compensation - stock options																		5,250,217						5,250,217
Stock-based compensation - stock warrants																		358,637						358,637
Issuance of Class D preferred stock				$ 309														64,787,240						64,787,549
Issuance of Class C Milestone Shares							$ 111											4,999,909						5,000,020
Issuance of Class B-1 Milestone Shares										$ 101								2,499,899						2,500,000
Exercise of stock options													$ 21					520,585						520,606
Exercise of stock options (in shares)													207,000
Exercise of stock warrant													$ 14					340,986						341,000
Exercise of stock warrant (in shares)													138,000
Issuance of stock (in shares)				3,093,092			1,102,945			1,011,721
Sixeva Liquidation																			(57)					(57)
Net loss																			(38,473,844)					(38,473,844)
Balance at the end of the period at Dec. 31, 2015				$ 309			$ 237			$ 324			$ 682					115,723,046	(58,550,520)					$ 57,174,078
Balance at the end of the period (in shares) at Dec. 31, 2015				3,093,092			2,365,020			3,237,528			6,817,093
Increase (Decrease) in Redeemable Common Stock
Shares conversion amount	$ (1,032,909)		$ (309)		$ (237)			$ (324)
Shares conversion (in shares)	(456,043)		(3,093,092)		(2,365,020)			(3,237,528)
Balance at the end of the period (in shares) at Dec. 31, 2016																								0
Increase (Decrease) in Stockholders' Equity (Deficit)
Stock based compensation-restricted stock													$ 175					10,370,762						$ 10,370,937
Stock based compensation-restricted stock (in shares)													1,750,794
Stock-based compensation - stock options																		16,415,008						16,415,008
Shares conversion amount	$ (1,032,909)		$ (309)		$ (237)			$ (324)
Share conversion, converted to common stock											$ 870			$ (892)						$ (892)
Share conversion, converted to common stock (in shares)											8,695,640
Exercise of stock options													$ 8					429,707						429,715
Exercise of stock options (in shares)													84,127
Exercise of stock warrant													$ 2					53,348						53,350
Exercise of stock warrant (in shares)													20,771
Shares converted to redeemable common stock amount											$ 45			1,032,864						1,032,909
Shares converted to redeemable common stock (in shares)											456,043
Issuance of stock											$ 528	$ 460		$ 95,348,158	$ 148,319,207					$ 95,348,686	$ 148,319,667
Issuance of stock (in shares)											5,277,941	4,597,645
Net loss																			(83,011,804)					(83,011,804)
Balance at the end of the period at Dec. 31, 2016													$ 2,770					$ 387,691,208	$ (141,562,324)					$ 246,131,654
Balance at the end of the period (in shares) at Dec. 31, 2016													27,700,054

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net loss	$ (83,011,804)	$ (38,473,844)	$ (15,705,776)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on sale of discontinued operations			145,199
Depreciation and amortization	64,630	13,463	3,350
Employee stock-based compensation	26,785,770	5,250,217	1,204,261
Stock-based third-party research and development		20,154,076	6,207,993
Disposal of fixed assets	24,011
Loss on extinguishment of debt			116,260
Changes in operating assets and liabilities
Prepaid and other current assets	(3,854,389)	(886,986)	(22,643)
Other long-term assets	(1,132,084)	(1,311,736)	(4,433)
Accounts payable	957,986	276,231	(92,582)
Accrued expenses	11,773,185	1,182,611	58,103
Accrued indemnification obligation	372,000		4,080,500
Other		(57)
Net cash provided by discontinued operations			8,731
Net cash used in operating activities	(48,020,695)	(13,796,025)	(4,001,037)
Cash flows from investing activities
Capital expenditures	(19,182,085)	(221,003)	(29,284)
Net cash used in investing activities	(19,182,085)	(221,003)	(29,284)
Cash flows from financing activities
Proceeds from issuance of convertible notes			1,000,000
Proceeds from exercise of stock options	429,714	520,606
Proceeds from exercise of stock warrants	53,350	341,000
Re-payment of notes payable			(350,000)
Proceeds from IPO and Follow-On Offering, net of issuance costs	246,489,901
Payment of deferred IPO costs	(1,592,206)
Net cash provided by financing activities	245,380,759	73,149,175	7,150,034
Net increase in cash and cash equivalents	178,177,979	59,132,147	3,119,713
Cash and cash equivalents, Beginning of Period	62,251,860	3,119,713
Cash and cash equivalents, End of Period	$ 240,429,839	62,251,860	3,119,713
Supplemental Cash Flow Information
Cash paid for interest		14,745	35,025
Supplemental Disclosure of Non-cash Investing and Financing Activities
Conversion of accrued legal fees into common stock			102,300
Conversion of convertible notes into Class B-1 and Class C preferred stock			1,000,000
Deferred issuance costs for planned initial public offering in accrued expenses		371,043
Class B Preferred Stock
Cash flows from financing activities
Proceeds from issuance of common stock		2,500,000	2,000,000
Class C Preferred Stock
Cash flows from financing activities
Proceeds from issuance of common stock		5,000,020	$ 4,500,034
Class D Preferred Stock
Cash flows from financing activities
Proceeds from issuance of common stock		$ 64,787,549

Background

Background	12 Months Ended
	Dec. 31, 2016
Background
Background	1. Background AveXis, Inc. was formed on March 8, 2010 in the state of Delaware as Biolife Cell Bank, LLC. In January 2012, the Company converted from a limited liability company to a corporation, Biolife Cell Bank, Inc. In January 2014, the Company amended and restated its Certificate of Incorporation to change its name to AveXis, Inc. ("AveXis" or "the Company"). The Company is a clinical-stage gene therapy company dedicated to developing and commercializing gene therapy treatments for patients suffering from rare and life-threatening neurological genetic diseases. The Company's initial product candidate, AVXS-101, is a gene therapy product candidate currently in a Phase 1 clinical trial for the treatment of spinal muscular atrophy, ("SMA"), Type 1, the leading genetic cause of infant mortality. Liquidity and Risks As of December 31, 2016, the Company generated an accumulated deficit of $141,562,324 since inception and had cash and cash equivalents of $240,429,839. The Company believes its cash and cash equivalents as of December 31, 2016, are sufficient cash resources to allow the Company to fund its current operating plan through the first half of 2019. As the Company continues to incur losses, transition to profitability is dependent upon the successful manufacturing, development, approval, and commercialization of its product candidate and achieving a level of revenues adequate to support the Company's cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. Management intends to fund future operations through additional private or public debt or equity offerings and may seek additional capital through arrangements with strategic partners or from other sources. The Company is subject to risks common to companies in the biotechnology industry, including, but not limited to, development by the Company or its competitors of technological innovations, risks of failure of clinical studies, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and ability to transition from preclinical manufacturing to commercial production of products. Initial Public Offering On February 10, 2016, the Company completed an initial public offering ("IPO"), which resulted in the issuance and sale of 4,750,000 shares of its common stock at a public offering price of $20.00 per share, resulting in net proceeds of approximately $88,350,000 after deducting underwriting discounts. Upon the closing of the IPO, the 3,278,938 shares of Class B-1 preferred stock, 326,557 shares of Class B-2 preferred stock, 2,365,020 shares of Class C preferred stock and 3,105,000 of Class D preferred stock were automatically converted into shares of the Company's common stock. On March 3, 2016, the underwriters of the Company's IPO exercised their over-allotment option to purchase an additional 527,941 shares of the Company's common stock at the initial public offering price of $20.00 per share, resulting in additional net proceeds of approximately $9,800,000 after deducting underwriting discounts. Follow-On Public Offering On September 13, 2016, the Company completed an underwritten public offering (the "Follow-On Offering") of 4,887,500 shares of its common stock, 4,597,645 shares of which were issued and sold by the Company, including the exercise in full by the underwriters of their option to purchase 637,500 shares from the Company, and 289,855 shares of which were sold by PBM Capital Investments, LLC ("PBM"), an existing stockholder of the Company, each at a public offering price of $34.50 per share. After deducting the underwriting discounts and commissions, the net proceeds to the Company were approximately $149.1 million. The Company did not receive proceeds from the sale of the common stock by PBM.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements of the Company and its subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP"). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification ("ASC") and Accounting Standards Update ("ASU") of the Financial Accounting Standards Board ("FASB"). These consolidated financial statements are presented in U.S. Dollars. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the valuation of common stock, stock warrants and restricted stock, and the grant date fair value of stock options. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from such estimates. Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents. The Company generally invests its cash equivalents in checking accounts and money market funds held at mid-sized financial institutions. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Cash and Cash Equivalents Cash and cash equivalents consist of cash, deposits with banks and short term highly liquid money market instruments with remaining maturities at the date of purchase of 90 days or less. Property and Equipment Property and equipment consists of construction in progress associated with the Company's investment in its manufacturing facility, office furniture and equipment and is recorded at cost less accumulated depreciation. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Upon disposal, retirement or sale, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations. Property and equipment are depreciated on a straight-line basis over their estimated useful lives. The Company uses a life of five to ten years for office furniture and equipment. Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. The Company did not record an impairment during the year ended December 31, 2016. Segment Information The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company's singular focus is on developing and commercializing gene therapy treatments for patients suffering from rare and life-threatening neurological genetic diseases. All of the Company's tangible assets are held in the United States. Revenue Recognition To date, the Company has not generated any revenues from the commercial sale of its gene therapy product candidate. Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries, stock-based compensation and benefits, third party license fees, and external costs of outside vendors engaged to conduct manufacturing and preclinical development activities and clinical trials. Upfront and milestone payments made to third parties who perform research and development services on the Company's behalf are expensed as services are rendered or when they no longer have alternative future use. Costs incurred in obtaining technology licenses are charged to research and development expense as acquired in-process research and development if the technology licensed has not reached technological feasibility and has no alternative future use. Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses. Stock-Based Compensation The Company accounts for its stock-based compensation awards in accordance with FASB ASC Topic 718, Compensation—Stock Compensation ("ASC 718"). ASC 718 requires all stock-based payments to employees, including grants of employee stock options and restricted stock units, to be recognized in the consolidated statements of operations based on their fair values. The Company's stock-based awards are subject to service and performance-based vesting conditions. Compensation expense related to awards to employees with only service-based vesting conditions is recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award was, in substance, multiple awards (the "Graded Vesting Attribution Method"), based on the estimated grant date fair value for each separately vesting tranche. Compensation expense related to awards to non-employees with only service-based vesting conditions is recognized based on the then-current fair value at each financial reporting date prior to the measurement date over the associated service period of the award, which is generally the vesting term, using the Graded Vesting Attribution Method. Compensation expense related to awards to employees with only performance-based vesting conditions is recognized based on the estimated grant date fair value over the requisite service period using the Graded Vesting Attribution Method to the extent achievement of the performance condition is probable. Compensation expense related to awards to non-employees only with performance-based vesting conditions is recognized based on the then-current fair value at each financial reporting date prior to the measurement date over the requisite service period using the Graded Vesting Attribution Method to the extent achievement of the performance condition is probable. The Company estimates the fair value of its option awards to employees and directors using the Black-Scholes option-pricing model, which requires the input of and use of subjective assumptions, including (i) the fair value of the underlying common stock, (ii) the expected stock price volatility, (iii) the calculation of expected term of the award, (iv) the risk-free interest rate, and (v) expected dividends. Due to the lack of company-specific historical and implied volatility data of its common stock, the Company has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. When selecting these public companies on which it has based its expected stock price volatility, the Company selected companies with comparable characteristics to it, including enterprise value, risk profiles, position within the industry, and with historical share price information sufficient to meet the expected term of the stock-based awards. The Company computes historical volatility data using the daily closing prices for the selected companies' shares during the equivalent period of the calculated expected term of the stock-based awards. The Company's estimates of expected term used in the Black-Scholes option pricing model were based on the estimated time from the grant date to the date of exercise. The risk-free interest rates for periods within the expected term of the option are based on the U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The Company has never paid dividends, and does not expect to pay dividends in the foreseeable future. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from its estimates. To date, a forfeiture rate of zero has been used to calculate stock-based compensation expense due to the Company's lack of historical experience. To the extent that actual forfeitures differ from the Company's estimates, the differences are recorded as a cumulative adjustment in the period the estimates were revised. Stock-based compensation expense recognized in the consolidated financial statements is based on awards that are ultimately expected to vest. Stock-based awards issued to non-employees, consisting of stock warrants and restricted common shares, are accounted for using the fair value method in accordance with ASC 505-50, Equity-Based Payments to Non-Employees . These stock warrants and restricted common shares have been granted in exchange for consulting services to be rendered, and vest according to certain service or performance conditions. In accordance with authoritative guidance, the fair value of non-employee stock-based awards is estimated on the date of grant, and subsequently revalued at each reporting period until the award vests or a measurement date has occurred using the Black-Scholes option-pricing model. Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders' equity (deficit) that result from transactions and economic events other than those with stockholders. There was no difference between net loss and comprehensive loss for each of the periods presented in the accompanying consolidated financial statements. Income Taxes The Company is a C corporation for federal and state income tax purposes. The Company recognizes deferred tax assets and liabilities for temporary differences between the financial reporting basis and the tax basis of its assets and liabilities and the expected benefits of net operating loss carryforwards. The impact of changes in tax rates and laws on deferred taxes, if any, is applied during the years in which temporary differences are expected to be settled and is reflected in the consolidated financial statements in the period of enactment. The measurement of deferred tax assets is reduced, if necessary, if, based on weight of the evidence, it is more likely than not that some, or all, of the deferred tax assets will not be realized. At December 31, 2016, 2015 and 2014, the Company has concluded that as a result of the accumulated losses to date and no near-term prospects for recognizing net income, a full valuation allowance is necessary for its deferred tax assets. Fourth Amended and Restated Certificate of Incorporation On February 1, 2016, the Company amended its certificate of incorporation such that the total authorized capital stock of the Company consisted of 30,000,000 shares of common stock, $0.0001 par value per share, 3,278,938 shares of Class B-1 preferred stock, $0.0001 par value per share, 326,557 shares of Class B-2 preferred stock, $0.0001 par value per share, 2,365,020 shares of Class C preferred stock, $0.0001 par value per share, 3,105,000 shares of Class D preferred stock, $0.0001 par value per share and 1,000,000 shares of preferred stock, $0.0001 par value per share. Additionally, the Company effected a stock split whereby each outstanding share of common stock and Class B-1, B-2, C and D preferred stock was converted into 1.38 shares of common stock and Class B-1, B-2, C and D preferred stock, respectively. All share and per share information presented in these condensed consolidated financial statements and accompanying footnotes has been retroactively adjusted to reflect the stock split. Fifth Amended and Restated Certificate of Incorporation On February 17, 2016, the Company amended its certificate of incorporation such that the total authorized capital stock of the Company consisted of 100,000,000 shares of common stock, $0.0001 par value per share, and 10,000,000 shares of preferred stock, $0.0001 par value per share. Recent Accounting Pronouncements In May 2014, the FASB and the International Accounting Standards Board (IASB) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The standard's core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under previous guidance. Early adoption is permitted after December 15, 2016, and the standard is effective for public entities for annual reporting periods beginning after December 15, 2017 and interim periods therein. The Company has not recognized revenue through December 31, 2016. The Company will evaluate the adoption of ASU 2014-09 when the Company begins to recognize revenue and determine the effects it may have on the Company's consolidated financial statements. In June 2014, the FASB issued ASU No. 2014-12, Compensation—Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could be Achieved after the Requisite Service Period ("ASU 2014-12"), which requires the Company to assess share-based awards with performance targets that could be achieved after the requisite service period for potential treatment as performance conditions. Under ASU 2014-12, compensation expense is to be recognized when the performance target is deemed probable and should represent the compensation expense attributable to the periods for which service has already been rendered. If the performance target is reached prior to achievement of the service period, the remaining unrecognized compensation cost should be recognized over the remaining service period. ASU 2014-12 is effective for annual and interim periods beginning after December 15, 2015, with early adoption permitted. The Company has adopted ASU 2014-12, which did not have a material effect on the Company's consolidated financial statements. In August 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("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 ("ASU 2014-15"), requiring management to evaluate whether events or conditions could impact an entity's ability to continue as a going concern for at least one year after the date that the financial statements are issued and to provide disclosures if necessary. Disclosures will be required if conditions give rise to substantial doubt and the type of disclosure will be determined based on whether management's plans will be able to alleviate the substantial doubt. ASU 2014-15 is effective for the Company beginning for annual periods ending after December 15, 2016, and for interim periods within annual periods ending after December 15, 2016. The Company has adopted ASU 2014-15, which did not have a material effect on the Company's consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes ("ASU 2015-17"). To simplify presentation, the new guidance requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. As a result, each jurisdiction will now only have one net noncurrent deferred tax asset or liability. ASU 2015-17 is effective for public business entities in fiscal years beginning after December 15, 2016, including interim periods within those years. Early adoption is permitted for all entities as of the beginning of an interim or annual reporting period. The Company is evaluating the adoption of ASU 2015-17, but has not determined the effects it may have on the Company's consolidated financial statements. In February 2016, the FASB issued Accounting Standards Codification ("ASC") No. 2016-02, Leases ("ASC 842"). The guidance requires lessees to recognize almost all leases on their balance sheet as a right-of-use asset and a lease liability. For income statement purposes, the FASB retained a dual model, requiring leases to be classified as either operating or finance. Lessor accounting is similar to the current model, but updated to align with certain changes to the lessee model and the new revenue recognition standard. Existing sale-leaseback guidance, including guidance for real estate, is replaced with a new model applicable to both lessees and lessors. ASC 842 is effective for fiscal years beginning after December 15, 2018. The Company is evaluating the adoption of ASC 842, but has not determined the effects it may have on the Company's consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"), which requires the Company to recognize the income tax effects of awards in the income statement when the awards vest or are settled. ASU 2016-09 is effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company has adopted ASU 2016-09, which did not have a material effect on the Company's consolidated financial statements. In August 2016, the FASB issued Accounting Standards Update, or ASU, 2016-15, Statement of Cash Flows (Topic 230). ASU 2016-15 is intended to reduce the diversity in practice regarding how certain transactions are classified within the statement of cash flows. ASU 2016-15 is effective for public business entities for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted with retrospective application. The Company is evaluating the adoption of ASU 2016-15, but has not determined the effects it may have on the Company's consolidated financial statements. Deferred Initial Public Offering Costs Deferred initial public offering costs, which primarily consist of direct, incremental legal, accounting and other professional fees relating to the IPO, are included in other long-term assets in the consolidated balance sheet as of December 31, 2015. These deferred costs were offset against the IPO proceeds upon the consummation of the offering. As of December 31, 2016 and 2015, the Company deferred $0 and $1,624,040 of IPO-related costs.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2016
Discontinued Operations
Discontinued Operations	3. Discontinued Operations On January 30, 2014, the Company sold its entire equity interest in Biolife Cell Bank Dallas, LLC ("Biolife Dallas") back to Biolife Dallas in exchange for nominal consideration and resigned from its position as a director of Biolife Dallas. Additionally, the Company sold all of its equity interests in the two wholly-owned subsidiaries through which it previously owned the equipment and intellectual property assets necessary to conduct the stem cell business conducted by Biolife Dallas. As a result of these transactions, the Company exited the stem cell business. In connection with the above transactions, the Company recognized a loss from discontinued operations of $0.2 million during the year ended December 31, 2014. The Company had no corresponding results from discontinued operations for the years ended December 31, 2016 and 2015, respectively.

Collaboration and License Agree

Collaboration and License Agreements	12 Months Ended
	Dec. 31, 2016
Collaboration and License Agreements
Collaboration and License Agreements	4. Collaboration and License Agreements Nationwide Children's Hospital In October 2013 (the "Effective Date"), the Company entered into an Exclusive License Agreement (the "Nationwide License"), which agreement was amended and restated in its entirety in January 2016, with Nationwide Children's Hospital ("NCH"). Under the terms of the agreement, NCH granted the Company an exclusive, non-transferable, worldwide license to certain patents held by NCH for the therapy and treatment of SMA. The Company was also provided a license to the Investigational New Drug application ("IND") for AVXS-101 (the "Product Candidate") and was provided the right to become sponsor of the IND after completion of the Phase 1 clinical trial. On October 14, 2015, the Company exercised the option and, as of November 6, 2015, the Company became the sponsor of the IND. Additionally, the Company was provided the U.S. marketing rights to the product upon receipt of regulatory approval. The Company is responsible for all clinical trial costs incurred by NCH that are not covered by third party research grants and the Company committed to spend not less than $9,400,000 for the development of the Product Candidate during the first eight years of the Nationwide License. Amounts incurred by NCH and reimbursed by the Company for the years ended December 31, 2016, 2015 and 2014 were $504,866, $570,299 and $341,482, respectively and are included in research and development expense in the consolidated statements of operations. Aggregate development costs, as defined in the Nationwide License, incurred by the Company through December 31, 2016 and 2015 were $41,167,949 and $9,890,947, respectively and achieve the committed contractual spend under the Nationwide License. As consideration for the Nationwide License, on the Effective Date, the Company agreed to issue 331,053 shares of its common stock to NCH (the "Up-front Shares"), which represented 3% of the Company's outstanding capital stock on a fully-diluted basis. Additionally, the Company agreed to make certain future milestone payments totaling $125,000 upon achievement of certain regulatory milestones and agreed to reimburse NCH, upon the successful completion of an additional financing round, the amount of $83,163 to cover past patent costs and expenses incurred by NCH prior to the Effective Date. These patent reimbursement costs are included in research and development expense for the year ended December 31, 2014. The Nationwide License provides that for the 30 day period immediately following FDA approval of the Biologics License Application ("BLA"), NCH shall have the option (if it owns at least 50% of the shares issued to it pursuant to the agreement) to sell all, but not less than all, of the Up-front Shares back to the Company at a per share price equal to two times the price per share of preferred stock sold by the Company in its Class B Financing ($2.47 per share), with such consideration to be paid by the Company in four equal quarterly installments (the "Royalty Option"). If the Royalty Option is exercised, the Company shall pay a low single digit royalty on net sales, if any, of the Product Candidate during the term of the Nationwide License, subject to certain annual minimums. In addition, the Company must pay NCH a portion of sublicensing revenue received from its sublicense of the licensed technology at percentages between low-double digits and low-teens. The rights granted to the Company under the Nationwide License represent distinct components that need to be combined with other licensed intellectual property and know how in order to complete the clinical development of AVXS-101 and have no alternative future use. Additionally, the Company did not acquire any employees in connection with the Nationwide License. As a result of the above, and the early-stage nature of the licensed technology, the Company concluded that the acquired rights did not meet the definition of a business, and therefore the Company accounted for the Nationwide License as an asset acquisition and expensed such amounts as research and development expense. The Company recognized research and development expense of $345,447 in its consolidated financial statements for the year ended December 31, 2013, representing the fair value of the Up-front Shares issued to NCH as of the Effective Date. Since NCH can require the Company to repurchase the Up-front Shares upon exercise of the Royalty Option, the fair value of the Up-front Shares as of the Effective Date of the Nationwide License is reflected as redeemable common stock on the Company's consolidated balance sheet as of December 31, 2015. In addition to the above, the Nationwide License granted NCH anti-dilution protection on its 3% equity ownership of the Company's outstanding capital stock on a fully-diluted basis until such time that the Company achieved a $50,000,000 market capitalization, and required that the Company file a registration statement for an initial public offering of its common stock within ninety days of the Effective Date. Failure to do so would constitute a material breach of the agreement and would allow NCH to terminate the Nationwide License. On January 13, 2014, the Nationwide License was amended to delay the requirement to file a registration statement to within 30 calendar days of NCH providing written notice to the Company that NCH had dosed the seventh patient in the Phase 1 clinical trial, and the anti-dilution protection afforded to NCH was extended until such time as the Company achieved a $100,000,000 market capitalization. In consideration for this amendment the Company agreed to pay to NCH an aggregate of $50,000, with $20,000 payable on the amendment date, and three $10,000 payments payable within ten days of the dosing of each of the first, second and fourth patients in the Phase 1 clinical trial. Such amount is included in research and development expense for the year ended December 31, 2014. In August 2014, the Company issued an additional 86,725 common shares to NCH pursuant to the anti-dilution provisions of the Nationwide License. The Company recognized additional research and development expense of $214,298, in its consolidated financial statements for the year ended December 31, 2014, representing the fair value of the additional common shares that were granted. In March 2015, the Company issued an additional 34,463 common shares to NCH, and in May 2015, the Company issued an additional 3,802 common shares to NCH in each case pursuant to the anti-dilution provisions of the Nationwide License. The Company recognized additional research and development expense of $473,164 in its consolidated financial statements for the year ended December 31, 2015, representing the fair value of the additional common shares that were granted. NCH's anti-dilution protection right expired on May 29, 2015 upon achievement by the Company of a $100,000,000 market capitalization. On April 23, 2015, the Nationwide License was again amended to further extend the filing deadline for a registration statement to December 31, 2015 in exchange for a $100,000 payment by the Company to NCH. Such amount is included in research and development expense for the year ended December 31, 2015. On October 14, 2015, the Company and NCH entered into an amendment to the Nationwide License. The amendment permits the Company to submit to the FDA for the transfer of the IND and associated regulatory filing to the Company and for the Company to become the sponsor of such IND. Contemporaneous with the execution of this amendment, the Company and NCH submitted the requisite documents to the FDA to initiate the transfer process. On November 6, 2015, the FDA approved the Company's sponsorship of such IND. The Nationwide License commenced on the Effective Date and terminates on the earliest of (a) the last to expire of the licensed patents or (b) 10 years from the date of first commercial sale of the Product Candidate. The Nationwide License can also be terminated (i) by the Company for convenience at any time after the first anniversary of the Effective Date upon six months prior written notice, (ii) by either party in the event of an uncured breach upon thirty days written notice, (iii) by NCH upon the bankruptcy/insolvency of the Company, and (iv) by NCH if it is sued by the Company for anything other than breach of the agreement. On January 13, 2016 (the "Amended and Restated Nationwide License Effective Date"), the Company and NCH amended and restated the Nationwide License (the "Amended and Restated Nationwide License") in its entirety. The Amended and Restated Nationwide License grants the Company an exclusive, non-transferable (except to a transfer to an affiliate or in other specified circumstances), sublicensable, worldwide license to certain patents held by NCH for the therapy and treatment of SMA. NCH acknowledged that, as of the date of the Amended and Restated Nationwide License, the Company had fulfilled its requirement to spend not less than $9,400,000 for the development of the Product Candidate in whole. The Royalty Option expired upon the effectiveness of the Amended and Restated Nationwide License. Accordingly, NCH no longer has the right to sell the Up-front Shares issued upon the Effective Date of the original NCH License back to the Company under any circumstances. Following the first commercial sale of the Product Candidate, the Company shall pay a low single digit royalty on net sales, if any, of the Product Candidate during the term of the Amended and Restated Nationwide License, subject to certain annual minimums. In addition, the Company must pay NCH a portion of sublicensing revenue received from its sublicense of the rights to the licensed technology at percentages between low-double digits and low-teens. The Amended and Restated Nationwide License commenced on the Amended and Restated Nationwide License Effective Date and terminates upon the expiration of the royalty term for the Product Candidate in each country in which it is sold. The Amended and Restated Nationwide License can also be terminated (i) by the Company for convenience at any time after the first anniversary of the Amended and Restated Nationwide License Effective Date upon six months prior written notice, (ii) by either party in the event of a material uncured breach upon thirty days written notice, (iii) by NCH upon the bankruptcy/insolvency of the Company, and (iv) by NCH if it is sued by the Company for anything other than a suit brought in response to any suit brought by NCH regarding the validity or enforceability of the NCH patents. REGENXBIO Inc. License On March 21, 2014, the Company entered into a License Agreement (the "ReGenX License") with ReGenX Biosciences, LLC, predecessor to REGENXBIO Inc. ("ReGenX"). Under the terms of the agreement, ReGenX granted the Company an exclusive, non-transferable, worldwide license to utilize ReGenX's proprietary adeno-associated virus ("AAV") gene delivery platform for the treatment of SMA, by in vivo gene therapy, using ReGenX's AAV9 gene delivery vector. As consideration for the ReGenX License, the Company agreed to make a $2,000,000 up-front payment (the "ReGenX Up-front Payment"), $1,000,000 of such amount paid in March 2014 and the remaining $1,000,000 paid by June 30, 2014. Additionally, the Company agreed to pay potential future milestones aggregating $12,250,000, and a mid-single to low-double digit royalty on net sales, if any, of the Company's Product Candidate, subject to reduction in specified circumstances; and lower mid-double digit percentages of any sublicense fees the Company receives from sublicenses of the licensed intellectual property rights. The Company also agreed to pay an annual maintenance fee on each anniversary of the effective date of the ReGenX License. A milestone payment of $0 and $250,000 and annual maintenance fee of $50,000 and $50,000 are included in research and development expenses for the year ended December 31, 2016 and 2015, respectively. The rights granted to the Company under the ReGenX License represent distinct components that need to be combined with other licensed intellectual property and know how in order to complete the clinical development of AVXS-101. Additionally, the Company did not acquire any employees or manufacturing capabilities in connection with the ReGenX License. As a result, the Company accounted for the ReGenX License as an asset acquisition. The ReGenX License term continues until the last valid patent claim expires or lapses in all countries of the world. Additionally, the Company may terminate the ReGenX License at any time upon a specified notice period and ReGenX may terminate upon the breach or insolvency of the Company, if we are greater than a specified number of days late (after notice and cure periods) in paying money due under the ReGenX License or if the Company, its affiliates, or sublicensees challenges the ReGenX patents subject to the ReGenX License. Either party may terminate the ReGenX License for material breach if such breach is not cured within a specified number of days. Asklepios Biopharmaceutical, Inc. License On May 29, 2015, the Company and Asklepios Biopharmaceutical, Inc. ("AskBio") entered into a Non-Exclusive License Agreement (the "AskBio License"). Under the terms of the AskBio License, AskBio granted the Company a non-exclusive, non-transferable, worldwide license to certain patents and know how held by AskBio. As consideration for the AskBio License, the Company agreed to make a $1,000,000 up-front payment (the "AskBio Up-front Payment"), with $300,000 of such amount payable within thirty days of the effective date of the AskBio License, $300,000 payable within thirty days following the dosing of the first patient in our recently completed Phase 1 clinical trial of the Product Candidate and $400,000 payable upon the dosing of the ninth patient in the clinical trial, as well as potential future milestone payments aggregating $9,600,000, and a tiered royalty on net sales, if any, of the Company's Product Candidate, on a country-by-country basis, starting at percentages in the low-single digits and increasing to mid-single digits. These royalty rates are subject to potential reduction in specified circumstances, including, in the event the Company exercises its option to make a specified one-time royalty option fee payment to AskBio. The Company must also pay AskBio a low double digit percentage of all consideration the Company receives from any sublicense of the licensed technology. Additionally, the Company agreed to pay an annual maintenance fee of $50,000 on each anniversary of the effective date of the AskBio License. The rights granted to the Company under the AskBio License represent distinct components that need to be combined with other licensed intellectual property and know-how in order to complete the clinical development of AVXS-101. Additionally, the Company did not acquire any employees or manufacturing capabilities in connection with the AskBio License. As a result, the Company accounted for the AskBio License as an asset acquisition. The AskBio Up-front Payment of $1,000,000 is included in the research and development expense for the year ended December 31, 2015, and accrued annual maintenance fees of $50,000 and $16,941 are included in research and development expense for the years ended December 31, 2016 and 2015, respectively. The AskBio License term continues until the last valid patent claim expires or lapses in all countries of the world. Additionally, the Company may terminate the AskBio License at any time upon six months' notice and AskBio may terminate upon the breach (after notice and cure periods) or insolvency of the Company. Additionally, AskBio may terminate the AskBio License in the event the Company (i) researches, develops or commercializes any AAV-based treatment for hemophilia or (ii) undergoes a change in control or is otherwise acquired by a third party that researches, develops or commercializes any AAV-based treatment for hemophilia, in each case, until April 1, 2019, unless such change in control is first approved by AskBio, such approval not to be unreasonably withheld if the party in control following such a change of control event agrees to additional restrictive measures as reasonably proposed by AskBio in its sole discretion prior to such change of control respecting the use of the AskBio licensed technology.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2016
Property and Equipment, Net
Property and Equipment, Net	5. Property and Equipment, Net Property and equipment, net, consists of the following: December 31, December 31, Office furniture, equipment and leasehold improvements $ $ Construction in progress ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, gross Less: accumulated depreciation ) ) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Depreciation expense was $64,630, $13,463 and $3,350 for the years ended December 31, 2016, 2015 and 2014, respectively. Construction in progress increased by $23,161,828 for the year ended December 31, 2016. This is due to procurement of manufacturing equipment and construction within the Company's Libertyville, Illinois manufacturing facility. Non-cash capital expenditures included accounts payable and accrued expenses at December 31, 2016 was $4,871,547.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2016
Accrued Expenses
Accrued Expenses	6. Accrued Expenses Accrued expenses consist of the following: December 31, December 31, Accrued manufacturing development costs $ $ Accrued payroll, bonus and deferred compensation Accrued construction in progress — Accrued consulting — Accrued clinical trial costs Accrued professional fees Accrued severance Other ​ ​ ​ ​ ​ ​ ​ ​ Accrued expenses $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Accrued Indemnification Obligat

Accrued Indemnification Obligation	12 Months Ended
	Dec. 31, 2016
Accrued Indemnification Obligation
Accrued Indemnification Obligation	7. Accrued Indemnification Obligation In January 2014, the Company issued 2,334,391 shares of restricted common stock to a member of its Board of Directors (Dr. Brian Kaspar, see Note 10) pursuant to a consulting agreement for scientific advisory services to be performed by the director on behalf of the Company. In connection with the restricted stock purchase agreement, the Company agreed to indemnify Dr. Kaspar for any taxes, interest, fines, penalties or other costs and expenses that Dr. Kaspar may incur in the future should the Internal Revenue Service succeed in a tax determination that the stock price paid by Dr. Kaspar (which was par value) was lower than the fair market value of the stock on the date of grant. The indemnification term is in effect for six years after the due date of the tax return for the year in which the stock was issued. In January 2016, the Company entered into an employment agreement with Dr. Kaspar. In connection with the preparation of the Company's audited consolidated financial statements for the year ended December 31, 2014, the Company determined that the per share fair value of the Company's common stock on January 28, 2014, the grant date, was $1.51. As a result, the Company issued Dr. Kaspar an amended Form 1099 for the 2014 tax year reflecting an aggregate fair value of the restricted stock grant of $3,535,419. Due to the indemnity obligation contained in Dr. Kaspar's restricted stock purchase agreement, the Company will ultimately be required to reimburse Dr. Kaspar for the taxes he will pay following the amendment of Dr. Kaspar's 2014 personal income tax return. As a result, the Company has concluded that payment of such indemnity is probable as of December 31, 2016 and 2015. Additionally, the Company intends to gross-up such indemnification payment for the tax that will be payable by Dr. Kaspar on the indemnity payment. As a result, the Company has accrued $4,452,500 and $4,080,500 at December 31, 2016 and 2015, respectively, representing the Company's best estimate of the ultimate tax indemnification and gross-up payment to be made to Dr. Kaspar. The increase in the accrued indemnification obligation was due to the accrual of additional interest and state and local tax expense through December 31, 2016. The Company expects to pay this entire amount in 2017.

Capitalization

Capitalization	12 Months Ended
	Dec. 31, 2016
Capitalization
Capitalization	8. Capitalization On February 1, 2016 , the Company amended its certificate of incorporation to effect a stock split whereby each issued and outstanding share of common stock and Class B-1, B-2, C and D preferred stock was converted into 1.38 shares of common stock, Class B-1, B-2, C and D preferred stock, respectively. The par value per share was not adjusted as a result of this stock split. All share information presented in these consolidated financial statements and accompanying footnotes has been retroactively adjusted to reflect the increased number of shares resulting from this action. As of December 31, 2015, the authorized capital stock of the Company consisted of 1,000,000 shares of undesignated preferred stock, par value $0.0001 per share, 22,080,000 shares of common stock, par value $0.0001 per share, 3,278,938 shares of Class B-1 preferred stock, par value $0.0001 per share, 326,557 shares of Class B-2 preferred stock, par value $0.0001 per share and 2,365,020 shares of Class C preferred stock, par value $0.0001 per share, 3,105,000 shares of Class D preferred stock, par value $0.0001 per share. As of December 31, 2016, the authorized capital stock of the Company consisted of 10,000,000 shares of undesignated preferred stock, par value $0.0001 per share and no shares issued and outstanding, and 100,000,000 shares of common stock, par value $0.0001 per share and 27,700,054 shares issued and outstanding. On January 30, 2014, the Company entered into three separate Exchange Agreements pursuant to which JDH Investment Management ("JDH"), an entity affiliated with a founder and then Board member of the Company, exchanged 202,347 common shares held by it for 202,347 Class B-1 preferred shares, John Carbona exchanged 202,347 common shares held by him for 202,347 Class B-1 preferred shares and West Summit Investments, LP ("West Summit"), exchanged 202,347 common shares held by it for 202,347 Class B-1 preferred shares. The common shares received by the Company pursuant to these Exchange Agreements were cancelled and retired and ceased to be issued and outstanding. In connection with the Exchange Agreements, the Company reduced earnings available to common stockholders used in the calculation of basic and diluted net loss per common share for the year ended December 31, 2014 (see Note 11) by an aggregate of $387,098, representing the difference between the fair value of the Class B-1 preferred shares issued and the fair value of the common stock that was surrendered in the exchanges, which the Company has accounted for as a deemed preferred dividend on its common stock. Additionally, because Mr. Carbona was serving as the Company's chief executive officer at the time, the Company recognized stock-based compensation expense (see Note 10), in connection with Mr. Carbona's Exchange Agreement. On February 18, 2014, the Company entered into an Exchange Agreement with White Rock Capital Partners, L.P. ("White Rock") pursuant to which White Rock exchanged 303,518 common shares held by it for 303,518 Class B-1 preferred shares (the "White Rock Exchange Agreement"), and on February 27, 2014, the Company entered into an Exchange Agreement with NRM VII Holdings I LLC ("NRM"), pursuant to which NRM exchanged 303,518 common shares held by it for 303,518 Class B-1 preferred shares (the "NRM Exchange Agreement" and, together, the "Exchange Agreements"). The common shares received by the Company pursuant to these Exchange Agreements were cancelled and retired and ceased to be issued and outstanding. In connection with the Exchange Agreements, the Company reduced earnings available to common stockholders used in the calculation of basic and diluted net loss per common share for the year ended December 31, 2014 (see Note 11) by an aggregate of $479,471, representing the difference between the fair value of the Class B-1 preferred shares issued and the fair value of the common stock that was surrendered in the exchanges, which the Company has accounted for as a deemed preferred dividend on its common stock. Pursuant to the terms of the Company’s certificate of incorporation as in effect prior to the date of its IPO, in the event of any Liquidation Event, the aggregate assets available for distribution to the stockholders would be distributed as follows: • first to the holders of Class C and Class D preferred stock in an amount per share equal to their original issue price ($4.2299 per share for Class C and $21.0145 per share for Class D preferred stock); • then, to the holders of Class B preferred stock in an amount per share equal to their original issue price ($2.471 per share for Class B-1 and $2.572 per share for Class B-2 preferred stock); and • then, the remaining assets shall be distributed to all holders of common stock and Class B-1, B-2, C and D preferred stock ratably based on the number of shares held by each holder. The right to a preferential distribution held by the Class B-1, B-2, C and D preferred stockholders would terminate upon the conversion of the preferred stock to common stock upon the completion of a qualified IPO. Holders of common stock and Class B-1, B-2, C and D preferred stock voted together as a single class. The Class B-1, B-2, C and D preferred stockholders had certain customary protective provisions that allowed them to approve the liquidation, dissolution or merger of the Company, the payment of dividends, the amendment of the Company's certificate of incorporation, an IPO or offering of the Company's debt securities, capital expenditures above a specified threshold and changes in the authorized shares or preferences of the Company's capital stock. The Class B-1, B-2, C and D preferred shares were subject to proportional adjustment upon stock splits and stock dividends. The Class B-1, B-2, C and D preferred shares would automatically convert, on a one-for-one basis, into common stock upon a Qualified IPO or the affirmative vote of the holders of a majority of the issued and outstanding shares of Class B-1, B-2, C and D preferred stock. The Company's certificate of incorporation and the related Class B and C financing documents reference the legal form of the Class B-1, B-2, C and D preferred shares as "common stock." For GAAP purposes, the Class B-1, B-2, C and D shares were classified as preferred stock due to the preferential distributions that could have been received by the holders of such shares. Class B-1 and B-2 Preferred Stock On January 30, 2014, the Company entered into a Convertible Note and Class B Stock Purchase Agreement (the "Class B Purchase Agreement") with PBM Capital Investments, LLC ("PBM"). Under the Class B Purchase Agreement, the Company sold to PBM a $500,000 convertible promissory note (the "Class B Note") (see Note 9) and granted PBM an option (the "Class B Option") to purchase 809,385 shares of Class B-1 preferred stock at a purchase price of $2.47 per share and a warrant (the "Class B-2 Warrant") to purchase 130,623 shares of Class B-2 preferred stock at $2.57 per share (the "Class B Stock Closing"). To exercise the Class B Option, PBM was required to provide written notice of its intent on or before February 28, 2014, after which date the Class B Option would terminate. After the Class B Stock Closing, the Company also agreed to sell and PBM agreed to purchase, on the same terms and conditions, 1,011,721 additional shares of Class B-1 preferred stock (the "Class B-1 Milestone Shares") and a warrant to purchase 163,278 additional shares of Class B-2 preferred stock (the "Milestone Warrant") on the same terms and conditions. The Class B-1 Milestone Shares were to be sold and the Milestone Warrant was to be issued within ten days of the date that the Company certified that the data and safety monitoring board appointed by the FDA had approved the dosing of the 7 th patient in the Company's Phase 1 clinical trial. On February 27, 2014, PBM provided notice of its intent to exercise the Class B Option. On March 7, 2014, the Company issued to PBM 1,011,721 shares of Class B-1 preferred stock at $2.47 per share in exchange for $2,000,000 of cash and the conversion of the Class B Note. In conjunction with the purchase of the Class B-1 preferred stock, the Company also issued the Class B-2 Warrant to PBM to purchase 130,623 shares of Class B-2 preferred stock at an exercise price of $2.57 per share. In April 2015, the Company certified that the data and safety monitoring board appointed by the FDA had approved the dosing of the 7 th patient in the Company's Phase 1 clinical trial. As a result, on May 4, 2015, the Company issued the Class B-1 Milestone Shares and the Milestone Warrant to PBM in exchange for $2,500,000 of cash. The Class B-2 Warrant and the Milestone Warrant may be exercised by the holder, in whole or in part, upon the payment of the exercise price in cash. The Class B-2 Warrant and the Milestone Warrant terminate upon the earliest to occur of (a) the 10 year anniversary of their issuance date or (b) a liquidation event, as defined therein. Class C Preferred Stock On August 11, 2014, the Company entered into a Class C Stock Purchase Agreement with Deerfield Private Design Fund III ("Deerfield") and Roche Finance Ltd ("Roche"). At closing, Deerfield purchased 504,478 shares of Class C preferred stock at a price of $3.96 per share and converted the original principal amount and accrued and unpaid interest on a secured promissory note dated June 20, 2014 (see Note 9) in the original principal amount of $500,000 into 126,991 shares of Class C preferred stock at a conversion price of $3.96 per share. At closing, Roche purchased 630,606 shares of Class C preferred stock at a purchase price of $3.96 per share. After the initial closing, the Company agreed to sell, and Deerfield and Roche each agreed to purchase, an aggregate of 551,472 additional shares of Class C preferred stock at a purchase price of $4.53 per share (the "Class C Milestone Shares") upon the later to occur of the following milestones (the "Class C Milestone Event"): a) within 15 days of the date upon which the Company notifies both Deerfield and Roche that the dosing of the 6 th patient in the Phase 1 clinical trial has occurred; or b) the second business day of the calendar month immediately following notification of the dosing of the 6 th patient in the Phase 1 clinical trial. Neither Deerfield nor Roche was required to purchase any Class C Milestone Shares if either (A) the 6 th patient was not dosed by April 15, 2015, or, as of or prior to April 15, 2015, the clinical trial had been stopped, suspended or put on partial or complete hold for patient safety reasons. Either Deerfield or Roche was permitted, at their sole discretion, to purchase their portion of the Class C Milestone Shares at any time, irrespective of the occurrence of a Class C Milestone Event, by providing 5 days written notice. The Class C Milestone Event occurred in March 2015 and on March 17, 2015, the Class C Milestone Shares were purchased by Deerfield and Roche in exchange for an aggregate purchase price of $5,000,020 in cash. Class D Preferred Stock Issuance On September 3, 2015, the Company entered into a Class D Stock Purchase Agreement pursuant to which the Company issued and sold an aggregate of 3,093,092 shares of Class D preferred stock at a price per share of $21.01 for an aggregate of $64,787,549, net of issuance costs.

Convertible Notes

Convertible Notes	12 Months Ended
	Dec. 31, 2016
Convertible Notes
Convertible Notes	9. Convertible Notes Class B Note On January 30, 2014, the Company entered into the Class B Purchase Agreement with PBM (see Note 8). Under the Class B Purchase Agreement, the Company sold to PBM a $500,000 convertible promissory note (the "Class B Note") and granted PBM the Class B Option. The Class B Note had a stated maturity of January 31, 2016, and accrued interest at 8% per annum. The Class B Note could not be prepaid without the prior written consent of PBM. If the Company were to receive gross proceeds of $500,000 or more from the issuance or sale of any equity securities to PBM or another third party, any time prior to January 31, 2016, (a "PBM Qualified Financing"), the Class B Note would automatically convert, at the price per share paid by the investors in the PBM Qualified Financing, into the class of equity securities sold in the PBM Qualified Financing. If the Company completed a financing that was not considered a PBM Qualified Financing any time prior to January 31, 2016, PBM, at its option, could convert the Class B Note, at the price per share paid by the investors in such a financing transaction, into the class of equity securities sold in the financing transaction. Additionally, PBM, at its option, could elect to convert the Class B Note at any time prior to the earlier of the maturity date or the closing of a PBM Qualified Financing, into shares of the Company's Class B-1 preferred stock at a conversion price of $2.47 per share. Finally, if not earlier converted, The Class B Note would automatically convert into shares of the Company's Class B-1 preferred stock at a conversion price of $2.47 per share at maturity. The Company recorded the Class B Note in accordance with the guidance found in ASC 470-20. The conversion feature in the Class B Note qualifies for the exception from derivative accounting in accordance with ASC 815-40. The Company therefore allocated the $500,000 in proceeds received from PBM to the Class B Note, the Class B Option and the contingent Class B-1 Milestone shares based on their relative fair values. The fair value of the Class B Option on the date of issuance, as calculated using the Black-Scholes model was $112,835, using the following assumptions: exercise price of $2.47 per share; Class B-1 preferred stock price of $2.47 per share; volatility of 45%; term of one month; a dividend yield of 0%; and an interest rate of 0.40%. The fair value of the contingent Class B-1 Milestone Shares was determined to be $0 because the $2.40 purchase price was equal to the fair value of a Class B-1 share as of the contract date. As a result, the Company recorded a discount of $112,835 related to the Class B Option. On March 7, 2014, the Company completed a PBM Qualified Financing with PBM and the outstanding principal amount of the Class B Note was converted into 202,345 shares of Class B-1 preferred stock at a conversion price of $2.47 per share and a Class B-2 Warrant to purchase 32,652 shares of Class B-2 preferred stock at an exercise price of $2.57 per share. As a result, the unamortized debt discount associated with the Class B Option of $112,835 was recognized immediately as a loss on extinguishment of debt. Such amount has been recorded within interest expense in the consolidated statement of operations for the year ended December 31, 2014. On February 10, 2016, the Company completed its IPO, which resulted in the issuance and sale of 4,750,000 shares of its common stock at a public offering price of $20.00 per share, resulting in net proceeds of approximately $88,350,000 after deducting underwriting discounts. Upon the closing of the IPO, the 3,278,938 shares of Class B-1 preferred stock and 326,557 shares of Class B-2 preferred stock automatically converted into shares of the Company's common stock. Deerfield Convertible Note On June 19, 2014, the Company and Deerfield entered into a $500,000 secured promissory note (the "Deerfield Note"). The Deerfield Note accrued interest at a rate of 5% per year compounding annually on December 31 of each year. In connection with the issuance of the Deerfield Note, Deerfield was granted a security interest in the Company's intellectual property. The outstanding principal and interest on the Deerfield Note was convertible, at the option of Deerfield, upon consummation of a qualified financing (a "Deerfield Qualified Financing") or at any time in which amounts remain unpaid under the Deerfield Note into shares of the same class and series of capital stock of the Company issued to the other investors in the Deerfield Qualified Financing at a conversion price per share equal to the lowest price per share at which the Deerfield Qualified Financing securities are sold by the Company to the investors in the Deerfield Qualified Financing. If the Company failed to complete a Deerfield Qualified Financing, Deerfield would be entitled to a 2.5% origination fee on the principal amount of the Deerfield Note, as well as reimbursement of out of pocket expenses. The Company recorded the Deerfield Note in accordance with the guidance found in ASC 470-20. The conversion feature in the Deerfield Note qualifies for the exception from derivative accounting in accordance with ASC 815-40. Under ASC 470-20, the fair value of the liability component of the Deerfield Note was determined to be the principal amount of $500,000 as the Deerfield Note contained no additional conversion or embedded features. On August, 11, 2014, the Company completed a Deerfield Qualified Financing with Deerfield and the outstanding principal amount of, and interest and unpaid interest on, the Deerfield Note were converted into 126,991 shares of Class C preferred stock at a conversion price of $3.96 per share. On February 10, 2016, the Company completed its IPO, which resulted in the issuance and sale of 4,750,000 shares of its common stock at a public offering price of $20.00 per share, resulting in net proceeds of approximately $88,350,000 after deducting underwriting discounts. Upon the closing of the IPO, 2,365,020 shares of Class C preferred stock were automatically converted into shares of the Company's common stock.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2016
Stock-based Compensation
Stock-based Compensation	10. Stock-based Compensation 2014 Stock Plan (the "2014 Plan") and 2016 Equity Incentive Plan (the "2016 Plan") In May 2014, the Company's Board of Directors adopted the 2014 Stock Plan (the "2014 Plan"), and in January 2016, the Company adopted the 2016 Equity Incentive Plan (the "2016 Plan" and, together with the 2014 Plan, the "Plans"). The 2016 Plan became effective on February 10, 2016, or the IPO Date. On and after the IPO Date, no additional stock awards may be granted under the 2014 Plan. The Board may amend or suspend the 2016 Plan at any time, although no such action may materially impair the rights under any then-outstanding award without the holder's consent. The Company will obtain stockholder approval for any amendments to the 2016 Plan as required by law. No incentive stock options may be granted under the 2016 Plan after the tenth anniversary of the effective date of the 2016 Plan. Initially, the aggregate number of shares of the Company's common stock that was available to be issued pursuant to stock awards under the 2016 Plan was 4,339,451 shares, which was the sum of (1) 2,400,000 new shares, plus (2) the number of shares reserved for issuance under the 2014 Plan on the IPO Date, plus (3) any shares subject to outstanding stock awards that would have otherwise been returned to the 2014 Plan. Additionally, the number of shares of the Company's common stock reserved for issuance under the 2016 Plan will automatically increase on January 1 of each year, beginning on January 1, 2017 and continuing through and including January 1, 2026, by 4.0% of the total number of shares of the Company's capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by the Board. The maximum number of shares that may be issued pursuant to the exercise of incentive stock options under the 2016 Plan is 8,678,902 shares. The Company has not granted stock appreciation rights to directors, officers or employees under the Plan since its inception. The Company granted 57,500 restricted stock awards to several employees in August 2016. Options generally expire ten years following the date of grant. Options typically vest over a period of two to four years, but vesting provisions can vary by award based on the discretion of the Board of Directors. Certain awards issued by the Company include performance conditions that must be achieved in order for vesting to occur. Options to purchase common stock carry an exercise price equal to the estimated fair value of the Company's common stock on the date of grant. Options to purchase shares of the Company's common stock may be exercised by payment of the exercise price in cash, by the delivery of previously acquired shares of common stock having a fair value equal to the exercise price payable or the withholding of common shares equal to the fair value of the aggregate exercise price. Upon the termination of service of a holder of stock options awarded under the Plan, all unvested options are immediately forfeited and vested options may be exercised within three months of termination. Shares of common stock underlying awards previously issued under the Plan which are reacquired by the Company, withheld by the Company in payment of the purchase price, exercise price, or withholding taxes, expired, cancelled due to forfeiture, or otherwise terminated other than by exercise, are added to the number of shares of common stock available for issuance under the Plan. Shares available for issuance under the Plan may be authorized but unissued shares of the Company's common stock or common stock reacquired by the Company and held in treasury. The Plan expires ten years from the date it was approved by the Board of Directors. The following table summarizes stock option activity: Weighted Average Weighted Number of Remaining Aggregate Outstanding at December 31, 2015 $ $ Granted $ Exercised ) $ Cancelled or forfeited ) $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2016 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at December 31, 2015 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested at December 31, 2015 and expected to vest $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at December 31, 2016 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested and expected to vest at December 31, 2016 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (a) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in-the-money at December 31, 2015 and 2016. As of December 31, 2016, 1,704,840 shares of common stock, were available for future grants under the Plan. The total intrinsic value of options exercised during the year ended December 31, 2014, 2015 and 2016 was $0, $3,565,436 and $3,449,227, respectively. As of December 31, 2016, there was $20,583,606 of unrecognized stock-based compensation expense related to employees' awards that is expected to be recognized over a weighted-average period of 1.4 years. The Company has recorded aggregate stock-based compensation expense related to the issuance of stock option awards under the Plan in the consolidated statements of operations and comprehensive loss as follows: Year ended Year ended Year ended Research and development $ $ $ General and administrative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock Options Granted to Employees The weighted-average grant date fair value of options granted during the years ended December 31, 2016, 2015 and 2014 was $24.50, $16.44 and $1.47, respectively, on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions: Year ended Year ended Year ended Expected volatility % % % Risk-free interest rate % % % Expected term (in years) Expected dividend yield % % % Restricted Stock Units (RSUs) The Company recognized stock-based compensation expense of $758,637 during the year ended December 31, 2016. At December 31, 2016, there was $1,248,113 of unrecognized compensation cost related to unvested restricted stock units that will be recognized as expense over a weighted-average period of 1.2 years. A summary of the status of the Company's restricted stock units at December 31, 2016, and of changes in restricted stock units outstanding under the 2016 Plan for the year ended December 31, 2016, is as follows: Number Weighted Average Outstanding at December 31, 2015 — $ — Granted Vested — — Forfeited and cancelled — — ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2016 $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Company grants restricted stock units with service-based vesting terms. The outstanding service-based restricted stock units vest over a period of three years. For awards that vest subject to the satisfaction of service requirements, compensation expense is measured based on the fair value of the RSUs on the date of grant and is recognized as expense on a straight-line basis, net of estimated forfeitures, over the requisite service period. All restricted stock units issued vest over time as stipulated in the individual restricted stock unit agreements. In the event of a change in control, the unvested restricted stock units will be accelerated and fully vested immediately prior to the change in control. There are no performance-based features or market conditions in the Company's outstanding restricted stock units. Valuation of Common Stock Prior to the IPO, the Company estimated the fair value of common stock underlying stock option awards at the grant date of the award. Valuation estimates were prepared by management in accordance with the framework of the American Institute of Certified Public Accountants Practice Guide, with the assistance of independent third party valuations, and approved by the Company's Board of Directors. The Company's valuations of its common stock were based on a number of objective and subjective factors, including external market conditions affecting the Company's industry sector, the prices at which the Company sold shares of its common and preferred stock, and the likelihood of achieving a liquidity event such as an initial public offering. Restricted Stock Granted to Non-Employees In January 2014, the Company issued 2,334,391 shares of restricted common stock to Dr. Brian Kaspar pursuant to a consulting agreement for scientific advisory services. Of these shares, 583,597 common shares were vested at the time of grant and the remaining restricted shares were scheduled to vest in the amount of 25% per year on the second, third and fourth anniversary of the grant date pursuant to a restricted stock purchase agreement, which became effective upon the effectiveness of the consulting agreement. In January 2016, the Company entered into an employment agreement with Dr. Kaspar. Upon the effectiveness of the employment agreement, Dr. Kaspar's 1,750,794 unvested shares granted pursuant to the restricted stock purchase agreement vested in full. As a result of the vesting of the remainder of this award the Company recorded $10,370,762 of additional stock compensation expense for the year ended December 31, 2016, in research and development expenses, as compared to $19,322,275 and $5,749,791 of stock compensation expense recognized related to the grant for the years ended December 31, 2015 and 2014, respectively. The following table summarizes restricted stock activity: Number of Nonvested shares at December 31, 2015 Shares granted — Shares vested ​ ​ ​ ​ ​ Nonvested shares at December 31, 2016 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Warrants Granted to Non-Employees On August 5, 2014, the Company issued to Pavilion a warrant to purchase 138,000 shares of common stock at an exercise price of $2.47 per share (the "First Warrant"). The First Warrant became exercisable as follows: 69,000 shares were exercisable immediately upon issuance; 34,500 shares became exercisable upon the purchase by PBM of the Class B Milestone Shares; and 34,500 shares became exercisable on January 26, 2015. The First Warrant was exercised in full in May 2015. The First Warrant was revalued each period until the award vested. Compensation expense was recorded on a straight-line basis over the vesting period of each separated vesting tranche of the award. The First Warrant had a grant date fair value of $146,000. The Company recorded compensation expense of $0 and $358,637 in the years ended December 31, 2016 and 2015, respectively, related to the First Warrant, within research and development expense in the consolidated statements of operations. During the years ended December 31, 2016 and 2015, the total number of stock warrants exercised was 20,771 and 138,000, respectively, resulting in total proceeds of $53,350 and $341,000, respectively. As of December 31, 2016 and 2015, there were 305,775 and 326,556 common stock warrants vested and outstanding issued to non-employees, respectively, with a weighted-average exercise price of $2.57.

Net Loss Per Common Share

Net Loss Per Common Share	12 Months Ended
	Dec. 31, 2016
Net Loss Per Common Share
Net Loss Per Common Share	11. Net Loss Per Common Share Net Loss per Common Share Basic net loss per common share is computed using the weighted average number of common shares outstanding during the period. Diluted net loss per common share is computed using the sum of the weighted average number of common shares outstanding during the period and, if dilutive, the weighted average number of potential shares of common stock, including the assumed exercise of stock options, stock warrants and unvested restricted common stock. The Company applies the two-class method to calculate its basic and diluted net loss per share attributable to common stockholders, as its preferred stock and common stock are participating securities. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to common stockholders. However, the two-class method does not impact the net loss per share of common stock as the Company was in a net loss position for each of the periods presented and preferred stockholders do not participate in losses. For the years ended December 31, 2016, 2015 and 2014, the following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding because the effect would be anti-dilutive: Year ended Year ended Year ended Stock options issued and outstanding Stock warrants Unvested restricted stock units — — Unvested restricted common stock — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts in the table above reflect the common stock equivalents of the noted instruments. The following table summarizes the calculation of the basic and diluted net loss per common share: Year ended Year ended Year ended Numerator: Loss from continuing operations $ ) $ ) $ ) Less: deemed preferred dividends on common stock — — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable from continuing operations to common stockholders $ ) $ ) $ ) Loss from discontinued operations — — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders $ ) $ ) $ ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: Weighted-average basic and diluted common shares ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic and diluted net loss per common share from continuing operations $ ) $ ) $ ) Basic and diluted net loss per common share from discontinued operations — — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic and diluted net loss per common share $ ) $ ) $ ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Separation Agreement

Separation Agreement	12 Months Ended
	Dec. 31, 2016
Separation Agreement
Separation Agreement	12. Separation Agreement On April 22, 2015, John Carbona ceased to be an employee of the Company. In connection with the termination of his employment, the Company agreed to pay Mr. Carbona the amount of $535,000, consisting of a $500,000 severance benefit (the "Severance") and $35,000 of accrued and unused vacation (the "Vacation Pay"). The Severance was to be paid over a 12 month period in equal monthly installments. However, per the terms of the separation agreement, following Mr. Carbona's removal from the Board in June 2015, (i) 50% of the then unpaid portion of Severance due to Mr. Carbona was paid to Mr. Carbona in a lump sum within 30 days from the termination of his service on the Board and (ii) the remaining 50% of the unpaid Severance due Mr. Carbona was paid in equal installments over the lesser of (a) six months or (b) the remainder of the original 12 month period. The Vacation Pay was paid in a lump sum in May 2015. In connection with the transactions described above, the Company recorded a charge of $535,000 in its consolidated statements of operations for the year ended December 31, 2015. Such amount is included within general and administrative expense in the consolidated statement of operations. Additionally, the Company agreed to fully accelerate the vesting of 53,820 unvested stock options held by Mr. Carbona at the time of the termination of his employment. The Company determined that the acceleration of vesting was a Type III modification pursuant to ASC 718. Therefore, the Company recognized the incremental fair value of the awards as of the modification date and recognized the amount immediately since the awards did not require further service. In connection with this modification, the Company recorded a charge of $503,502 in its consolidated statement of operations for the year ended December 31, 2015. Such amount is included within general and administrative expense. In connection with the termination of his employment, Mr. Carbona also agreed to transfer to the Company all shares of Sixeva, Inc., a variable interest entity that the Company dissolved in October 2015, held by entities affiliated with him and to terminate the Cross Option.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies
Commitments and Contingencies	13. Commitments and Contingencies Operating Leases In March 2014, the Company entered into a lease agreement, which expires in April 2017, for approximately 2,418 square feet of office space in Dallas, Texas. The lease agreement provides for annual escalation in rent payments during the lease term. The Company is amortizing the escalation in rental payments on a straight-line basis over the term of the lease. The Company also leases a 15,668 square foot facility for its corporate headquarters in Bannockburn, Illinois, pursuant to a lease that expires in July 2024. The lease agreement provides for annual escalation in rent payments during the lease term. The Company is amortizing the escalation in rental payments on a straight-line basis over the term of the lease. The Company also leases a 1,318 square foot facility in Columbus, Ohio for research and development activities, pursuant to a lease that expires in March 2019. In March 2016, the Company entered into a lease agreement, which expires in August 2026, for approximately 48,529 square feet of warehouse and office space Libertyville, Illinois. A portion of the warehouse space was converted into manufacturing space. The lease agreement provides for annual escalation in rent payments during the lease term. The lease agreement provides the Company with a one-time right to terminate the lease effective as of the last day of the ninety-sixth full calendar month of the lease subject to a termination fee. The Company is amortizing the escalation in rental payments on a straight-line basis over the term of the lease. Future minimum lease payments under all of the Company's leases are as follows: Year ending December 31, 2017 $ 2018 2019 2020 2021 Thereafter ​ ​ ​ ​ ​ Total $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Rent expense on all operating leases amounted to $283,892, $91,959 and $38,824 for the years ended December 31, 2016, 2015 and 2014, respectively. License Agreements See Note 4 for information regarding licenses entered into by the Company. These agreements may require the Company to make future payments relating to sublicense fees, milestone fees and royalties on future sales, if any, of the Product Candidate. Guarantees and Indemnifications The Company has accrued $4,452,500 and $4,080,500 at December 31, 2016 and 2015, respectively, representing the Company's best estimate of the ultimate tax indemnification and gross-up payment to be made to a former consultant pursuant to a tax indemnification granted to such consultant in connection with a restricted common stock grant (see Note 7). Additionally, in the normal course of business, the Company has entered into agreements that contain a variety of representations and provide for general indemnification. The Company's exposure under these agreements is unknown because it involves claims that may be made against the Company in the future. To date, the Company has not paid any claims or been required to defend any action related to these indemnification obligations. As of December 31, 2016 and 2015, the Company did not have any material indemnification claims related to these agreements that were probable or reasonably possible and consequently has not recorded any related liabilities. Litigation On September 8, 2016, Sophia's Cure Foundation ("SCF"), a non-profit 501(c)(3) public charity, filed a complaint in U.S. District Court, Southern District of Ohio, naming as defendants Nationwide Children's Hospital ("NCH") and other entities affiliated with NCH, the Company and certain of the Company's present and former executives (the "Complaint"). According to the complaint, in 2012, SCF and Nationwide Children's Hospital Foundation ("NCH Foundation") entered into a donation agreement under which SCF provided NCH a gift of $550,000 to fund clinical work associated with the study of the product candidate that the Company now refers to as AVXS-101 for SMA Type 1 patients, and NCH Foundation agreed in such donation agreement to reference SCF as the "primary sponsor" of such clinical work in all publications issued by NCH Foundation. The complaint also alleges that NCH breached the donation agreement by not naming SCF as the sponsor of the investigational new drug application (the "IND") that it filed for AVXS-101. Additionally, the complaint alleges that the Company and the named Company executives tortiously interfered with SCF's rights under the donation agreement by assuming sponsorship of the IND under the NCH License. There is no contractual relationship between the Company and SCF. The complaint seeks, among other relief, monetary damages of $500 million and equitable relief, including taking steps to designate SCF as the sponsor of the IND. The Company filed a motion to dismiss this action on October 28, 2016. On December 5, 2016, SCF filed an amended complaint, asserting similar allegations against the Company as in the original complaint. The Company filed a motion to dismiss the amended complaint on December 19, 2016. Under the current schedule, SCF's response is due on March 20, 2017. The Company believes that the complaint is without merit and intends to vigorously defend itself and its current executives from the allegations. The Company views the probability of loss in this matter to be remote. Lawsuits may be asserted against the Company in the normal course of business. Based on information currently available, management believes that the disposition of any matters, including the matter involving SCF described above, will not have a material adverse effect on the financial position, results of operations or cash flows of the Company.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Taxes
Income Taxes	14. Income Taxes There is no provision for income taxes because the Company has historically incurred operating losses and maintains a full valuation allowance against its net deferred tax assets. A reconciliation of the difference between the federal statutory rate and the effective income tax rate as a percentage of income before taxes for the years ended December 31, 2016, 2015 and 2014, respectively, is as follows: Year ended Year ended Year ended Amount Tax Rate Amount Tax Rate Amount Tax Rate Federal statutory rate $ ) % $ ) % $ ) % Permanent differences )% )% )% State taxes ) % ) % — % Research and development credit ) % ) % ) % Valuation allowance )% )% )% Other )% )% )% ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective income tax rate $ — % $ — % $ — % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company's deferred taxes at December 31, 2016 and 2015 were as follows: December 31, 2016 2015 Assets Liabilities Assets Liabilities Current: Accrued Expenses $ $ — $ $ — Other — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Subtotal — — Valuation allowance ) — ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net current deferred taxes $ $ $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long Term: Net operating loss carryforwards $ $ — $ $ — Capital loss carryforward — — — Research & development credit — — Capitalized research and development — — — Amortization — — Stock options and warrants — — Fixed assets — ) — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Subtotal ) ) Valuation allowance ) ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total long-term deferred taxes $ $ ) $ $ ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net deferred tax assets/(liabilities) $ — $ — $ — $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A valuation allowance equal to 100% of the net deferred tax assets has been established because of the uncertainty of realization of the deferred tax assets due to the absence of earnings history. The Company's valuation allowance relates primarily to net operating loss carryforwards. As of December 31, 2016 and 2015, the Company had federal net operating loss carryforwards available to reduce future taxable income of approximately $34,551,469 and $16,525,413, respectively, which expire beginning in 2032. If not used, these net operating loss carryforwards may be subject to limitation under Internal Revenue Code Section 382 should there be a greater than 50% ownership change as determined under the regulations. During 2016, the Company performed a detailed analysis of historical and/or current Section 382 ownership changes that may limit the utilization of net operating loss carryovers. From their entire federal net operating loss carryforward of $34,551,469 as of December 31, 2016, approximately $25,590,114 is available for immediate use based on the IRC 382 analysis performed. The remaining net operating loss carryforward will become available by the end of 2018 unless there is another greater than 50% change in ownership. As of December 31, 2016 and 2015, the Company has unused federal research and development carryforwards of approximately $13,733,227 and $262,831, respectively, which will begin to expire in 2034. A portion of these carryforwards and tax credits may expire before becoming available to reduce future income tax liabilities. The table below details the changes to the Company's valuation allowance for the years ended December 31, 2016 and 2015: Valuation allowance at December 31, 2014 $ Additions for 2015 Change in tax rates ​ ​ ​ ​ ​ Valuation allowance at December 31, 2015 Additions for 2016 Change in tax rates — ​ ​ ​ ​ ​ Valuation allowance at December 31, 2016 $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions
Related Party Transactions	15. Related Party Transactions The Company entered into the following related party transactions: In January 2014, the Company sold the 1,000 shares of Biolife Cell Bank Management, LLC and the 1,000 shares of Biolife Cell Bank Intellectual Property, LLC, held by it, to DGG Holdings, an entity controlled by Dr. David Genecov, a former member of the Company's Board and the principal of West Summit. The Company's former chief executive officer, Mr. Carbona, was the holder, through affiliated entities, of all of the outstanding shares of common stock of Sixeva until the termination of his employment with the Company and the transfer of such shares to the Company in April 2015 (see Note 11). On March 7, 2014, the Company entered into a Services Agreement (the "Services Agreement") with PBM to engage PBM for certain scientific and technical consultation, accounting and back office support services. The Company agreed to pay PBM $205,000 annually for these services. The Services Agreement had an initial term of 18 months but was terminated on September 7, 2014. The Company recognized $103,180 of expense related to the Services Agreement during the year ended December 31, 2014 and these amounts are included within general and administrative expense in the Company's consolidated statements of operations. In January 2014, the Company granted 2,334,391 restricted shares of common stock to a member of the Company's Board of Directors pursuant to a consulting agreement for scientific advisory services to be performed by the Board member on behalf of the Company (see Note 7). Additionally, such Board member and consultant was, at the time, a full time employee of NCH, although he is currently on entrepreneurial leave from NCH. The Company reimbursed the consultant $33,088 for the legal fees incurred in connection with the negotiation of the consulting agreement. The inventors of the licensed NCH intellectual property, which include the consultant, are entitled to a certain share of the revenues received by NCH under the Nationwide License. (see Note 4). On March 17, 2014, the Company entered into the Letter Agreement with, and granted common stock warrants to, Pavilion (see Note 8). The principal of Pavilion is an employee of PBM. Two stockholders of the Company, who are each affiliated with a director of the Company and who collectively beneficially own, as defined by SEC rules, 11.8% of the Company's common stock on an as-converted basis, are also significant stockholders of ReGenX. One of these stockholders is also affiliated with a member of the board of directors of ReGenX. As such, ReGenX is currently deemed to be a related party. However, the stockholder affiliated with the ReGenX director was not a stockholder of the Company, nor was it affiliated with a director of the Company, at the time the ReGenX License (see Note 4) was executed.

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2016
Retirement Plan
Retirement Plan	16. Retirement Plan The Company initiated a discretionary Simple IRA Plan offered to all of its employees. Under the Simple IRA Plan, employees may defer income on a tax-exempt basis, subject to limitations under the Internal Revenue Code of 1986, as amended. Under the Simple IRA Plan, the Company may make discretionary matching contributions. Company contributions expensed in 2016 totaled $145,921.

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information (Unaudited)
Quarterly Financial Information (Unaudited)	17. Quarterly Financial Information (Unaudited) Summarized quarterly financial information for each of the years ended December 31, 2016 and 2015 are as follows: Quarter Ended December 31, September 30, June 30, March 31, Revenue $ — $ — $ — $ — Loss from operations $ ) $ ) $ ) $ ) Interest income $ $ $ $ Net loss and comprehensive loss $ ) $ ) $ ) $ ) Basic and diluted net loss per common share $ ) $ ) $ ) $ ) Weighted-average basic and diluted common shares outstanding Quarter Ended December 31, September 30, June 30, March 31, Revenue $ — $ — $ — $ — Loss from continuing operations $ ) $ ) $ ) $ ) Other income $ $ $ $ Net loss $ ) $ ) $ ) $ ) Basic and diluted net loss per common share $ ) $ ) $ ) $ ) Weighted-average basic and diluted common shares outstanding

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements of the Company and its subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP"). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification ("ASC") and Accounting Standards Update ("ASU") of the Financial Accounting Standards Board ("FASB"). These consolidated financial statements are presented in U.S. Dollars.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the valuation of common stock, stock warrants and restricted stock, and the grant date fair value of stock options. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from such estimates.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents. The Company generally invests its cash equivalents in checking accounts and money market funds held at mid-sized financial institutions. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash, deposits with banks and short term highly liquid money market instruments with remaining maturities at the date of purchase of 90 days or less.
Property and Equipment	Property and Equipment Property and equipment consists of construction in progress associated with the Company's investment in its manufacturing facility, office furniture and equipment and is recorded at cost less accumulated depreciation. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Upon disposal, retirement or sale, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations. Property and equipment are depreciated on a straight-line basis over their estimated useful lives. The Company uses a life of five to ten years for office furniture and equipment.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. The Company did not record an impairment during the year ended December 31, 2016.
Segment Information	Segment Information The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company's singular focus is on developing and commercializing gene therapy treatments for patients suffering from rare and life-threatening neurological genetic diseases. All of the Company's tangible assets are held in the United States.
Revenue Recognition	Revenue Recognition To date, the Company has not generated any revenues from the commercial sale of its gene therapy product candidate.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries, stock-based compensation and benefits, third party license fees, and external costs of outside vendors engaged to conduct manufacturing and preclinical development activities and clinical trials. Upfront and milestone payments made to third parties who perform research and development services on the Company's behalf are expensed as services are rendered or when they no longer have alternative future use. Costs incurred in obtaining technology licenses are charged to research and development expense as acquired in-process research and development if the technology licensed has not reached technological feasibility and has no alternative future use.
Patent Costs	Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for its stock-based compensation awards in accordance with FASB ASC Topic 718, Compensation—Stock Compensation ("ASC 718"). ASC 718 requires all stock-based payments to employees, including grants of employee stock options and restricted stock units, to be recognized in the consolidated statements of operations based on their fair values. The Company's stock-based awards are subject to service and performance-based vesting conditions. Compensation expense related to awards to employees with only service-based vesting conditions is recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award was, in substance, multiple awards (the "Graded Vesting Attribution Method"), based on the estimated grant date fair value for each separately vesting tranche. Compensation expense related to awards to non-employees with only service-based vesting conditions is recognized based on the then-current fair value at each financial reporting date prior to the measurement date over the associated service period of the award, which is generally the vesting term, using the Graded Vesting Attribution Method. Compensation expense related to awards to employees with only performance-based vesting conditions is recognized based on the estimated grant date fair value over the requisite service period using the Graded Vesting Attribution Method to the extent achievement of the performance condition is probable. Compensation expense related to awards to non-employees only with performance-based vesting conditions is recognized based on the then-current fair value at each financial reporting date prior to the measurement date over the requisite service period using the Graded Vesting Attribution Method to the extent achievement of the performance condition is probable. The Company estimates the fair value of its option awards to employees and directors using the Black-Scholes option-pricing model, which requires the input of and use of subjective assumptions, including (i) the fair value of the underlying common stock, (ii) the expected stock price volatility, (iii) the calculation of expected term of the award, (iv) the risk-free interest rate, and (v) expected dividends. Due to the lack of company-specific historical and implied volatility data of its common stock, the Company has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. When selecting these public companies on which it has based its expected stock price volatility, the Company selected companies with comparable characteristics to it, including enterprise value, risk profiles, position within the industry, and with historical share price information sufficient to meet the expected term of the stock-based awards. The Company computes historical volatility data using the daily closing prices for the selected companies' shares during the equivalent period of the calculated expected term of the stock-based awards. The Company's estimates of expected term used in the Black-Scholes option pricing model were based on the estimated time from the grant date to the date of exercise. The risk-free interest rates for periods within the expected term of the option are based on the U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The Company has never paid dividends, and does not expect to pay dividends in the foreseeable future. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from its estimates. To date, a forfeiture rate of zero has been used to calculate stock-based compensation expense due to the Company's lack of historical experience. To the extent that actual forfeitures differ from the Company's estimates, the differences are recorded as a cumulative adjustment in the period the estimates were revised. Stock-based compensation expense recognized in the consolidated financial statements is based on awards that are ultimately expected to vest. Stock-based awards issued to non-employees, consisting of stock warrants and restricted common shares, are accounted for using the fair value method in accordance with ASC 505-50, Equity-Based Payments to Non-Employees . These stock warrants and restricted common shares have been granted in exchange for consulting services to be rendered, and vest according to certain service or performance conditions. In accordance with authoritative guidance, the fair value of non-employee stock-based awards is estimated on the date of grant, and subsequently revalued at each reporting period until the award vests or a measurement date has occurred using the Black-Scholes option-pricing model.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders' equity (deficit) that result from transactions and economic events other than those with stockholders. There was no difference between net loss and comprehensive loss for each of the periods presented in the accompanying consolidated financial statements.
Income Taxes	Income Taxes The Company is a C corporation for federal and state income tax purposes. The Company recognizes deferred tax assets and liabilities for temporary differences between the financial reporting basis and the tax basis of its assets and liabilities and the expected benefits of net operating loss carryforwards. The impact of changes in tax rates and laws on deferred taxes, if any, is applied during the years in which temporary differences are expected to be settled and is reflected in the consolidated financial statements in the period of enactment. The measurement of deferred tax assets is reduced, if necessary, if, based on weight of the evidence, it is more likely than not that some, or all, of the deferred tax assets will not be realized. At December 31, 2016, 2015 and 2014, the Company has concluded that as a result of the accumulated losses to date and no near-term prospects for recognizing net income, a full valuation allowance is necessary for its deferred tax assets.
Fourth Amended and Restated Certificate of Incorporation	Fourth Amended and Restated Certificate of Incorporation On February 1, 2016, the Company amended its certificate of incorporation such that the total authorized capital stock of the Company consisted of 30,000,000 shares of common stock, $0.0001 par value per share, 3,278,938 shares of Class B-1 preferred stock, $0.0001 par value per share, 326,557 shares of Class B-2 preferred stock, $0.0001 par value per share, 2,365,020 shares of Class C preferred stock, $0.0001 par value per share, 3,105,000 shares of Class D preferred stock, $0.0001 par value per share and 1,000,000 shares of preferred stock, $0.0001 par value per share. Additionally, the Company effected a stock split whereby each outstanding share of common stock and Class B-1, B-2, C and D preferred stock was converted into 1.38 shares of common stock and Class B-1, B-2, C and D preferred stock, respectively. All share and per share information presented in these condensed consolidated financial statements and accompanying footnotes has been retroactively adjusted to reflect the stock split.
Fifth Amended and Restated Certificate of Incorporation	Fifth Amended and Restated Certificate of Incorporation On February 17, 2016, the Company amended its certificate of incorporation such that the total authorized capital stock of the Company consisted of 100,000,000 shares of common stock, $0.0001 par value per share, and 10,000,000 shares of preferred stock, $0.0001 par value per share.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB and the International Accounting Standards Board (IASB) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The standard's core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under previous guidance. Early adoption is permitted after December 15, 2016, and the standard is effective for public entities for annual reporting periods beginning after December 15, 2017 and interim periods therein. The Company has not recognized revenue through December 31, 2016. The Company will evaluate the adoption of ASU 2014-09 when the Company begins to recognize revenue and determine the effects it may have on the Company's consolidated financial statements. In June 2014, the FASB issued ASU No. 2014-12, Compensation—Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could be Achieved after the Requisite Service Period ("ASU 2014-12"), which requires the Company to assess share-based awards with performance targets that could be achieved after the requisite service period for potential treatment as performance conditions. Under ASU 2014-12, compensation expense is to be recognized when the performance target is deemed probable and should represent the compensation expense attributable to the periods for which service has already been rendered. If the performance target is reached prior to achievement of the service period, the remaining unrecognized compensation cost should be recognized over the remaining service period. ASU 2014-12 is effective for annual and interim periods beginning after December 15, 2015, with early adoption permitted. The Company has adopted ASU 2014-12, which did not have a material effect on the Company's consolidated financial statements. In August 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("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 ("ASU 2014-15"), requiring management to evaluate whether events or conditions could impact an entity's ability to continue as a going concern for at least one year after the date that the financial statements are issued and to provide disclosures if necessary. Disclosures will be required if conditions give rise to substantial doubt and the type of disclosure will be determined based on whether management's plans will be able to alleviate the substantial doubt. ASU 2014-15 is effective for the Company beginning for annual periods ending after December 15, 2016, and for interim periods within annual periods ending after December 15, 2016. The Company has adopted ASU 2014-15, which did not have a material effect on the Company's consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes ("ASU 2015-17"). To simplify presentation, the new guidance requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. As a result, each jurisdiction will now only have one net noncurrent deferred tax asset or liability. ASU 2015-17 is effective for public business entities in fiscal years beginning after December 15, 2016, including interim periods within those years. Early adoption is permitted for all entities as of the beginning of an interim or annual reporting period. The Company is evaluating the adoption of ASU 2015-17, but has not determined the effects it may have on the Company's consolidated financial statements. In February 2016, the FASB issued Accounting Standards Codification ("ASC") No. 2016-02, Leases ("ASC 842"). The guidance requires lessees to recognize almost all leases on their balance sheet as a right-of-use asset and a lease liability. For income statement purposes, the FASB retained a dual model, requiring leases to be classified as either operating or finance. Lessor accounting is similar to the current model, but updated to align with certain changes to the lessee model and the new revenue recognition standard. Existing sale-leaseback guidance, including guidance for real estate, is replaced with a new model applicable to both lessees and lessors. ASC 842 is effective for fiscal years beginning after December 15, 2018. The Company is evaluating the adoption of ASC 842, but has not determined the effects it may have on the Company's consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"), which requires the Company to recognize the income tax effects of awards in the income statement when the awards vest or are settled. ASU 2016-09 is effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company has adopted ASU 2016-09, which did not have a material effect on the Company's consolidated financial statements. In August 2016, the FASB issued Accounting Standards Update, or ASU, 2016-15, Statement of Cash Flows (Topic 230). ASU 2016-15 is intended to reduce the diversity in practice regarding how certain transactions are classified within the statement of cash flows. ASU 2016-15 is effective for public business entities for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted with retrospective application. The Company is evaluating the adoption of ASU 2016-15, but has not determined the effects it may have on the Company's consolidated financial statements.
Deferred Initial Public Offering Costs	Deferred Initial Public Offering Costs Deferred initial public offering costs, which primarily consist of direct, incremental legal, accounting and other professional fees relating to the IPO, are included in other long-term assets in the consolidated balance sheet as of December 31, 2015. These deferred costs were offset against the IPO proceeds upon the consummation of the offering. As of December 31, 2016 and 2015, the Company deferred $0 and $1,624,040 of IPO-related costs.

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2016
Property and Equipment, Net
Summary of property and equipment, net	December 31, December 31, Office furniture, equipment and leasehold improvements $ $ Construction in progress ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, gross Less: accumulated depreciation ) ) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Accrued Expenses
Schedule of accrued expenses	December 31, December 31, Accrued manufacturing development costs $ $ Accrued payroll, bonus and deferred compensation Accrued construction in progress — Accrued consulting — Accrued clinical trial costs Accrued professional fees Accrued severance Other ​ ​ ​ ​ ​ ​ ​ ​ Accrued expenses $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Stock-based Compensation
Summary of stock option activity	Weighted Average Weighted Number of Remaining Aggregate Outstanding at December 31, 2015 $ $ Granted $ Exercised ) $ Cancelled or forfeited ) $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2016 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at December 31, 2015 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested at December 31, 2015 and expected to vest $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at December 31, 2016 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested and expected to vest at December 31, 2016 $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (a) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in-the-money at December 31, 2015 and 2016.
Summary of aggregate stock-based compensation recorded in consolidated statements of operations and comprehensive loss	Year ended Year ended Year ended Research and development $ $ $ General and administrative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of grant date fair value and assumptions used in determining fair value of stock options	Year ended Year ended Year ended Expected volatility % % % Risk-free interest rate % % % Expected term (in years) Expected dividend yield % % %
Summary of restricted stock units activity	Number Weighted Average Outstanding at December 31, 2015 — $ — Granted Vested — — Forfeited and cancelled — — ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2016 $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of restricted stock activity	Number of Nonvested shares at December 31, 2015 Shares granted — Shares vested ​ ​ ​ ​ ​ Nonvested shares at December 31, 2016 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2016
Net Loss Per Common Share
Potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding	Year ended Year ended Year ended Stock options issued and outstanding Stock warrants Unvested restricted stock units — — Unvested restricted common stock — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of the basic and diluted net loss per common share	Year ended Year ended Year ended Numerator: Loss from continuing operations $ ) $ ) $ ) Less: deemed preferred dividends on common stock — — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable from continuing operations to common stockholders $ ) $ ) $ ) Loss from discontinued operations — — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable to common stockholders $ ) $ ) $ ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: Weighted-average basic and diluted common shares ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic and diluted net loss per common share from continuing operations $ ) $ ) $ ) Basic and diluted net loss per common share from discontinued operations — — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic and diluted net loss per common share $ ) $ ) $ ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies
Future minimum lease payments	Year ending December 31, 2017 $ 2018 2019 2020 2021 Thereafter ​ ​ ​ ​ ​ Total $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Taxes
Schedule of reconciliation of difference between federal statutory rate and effective income tax rate	Year ended Year ended Year ended Amount Tax Rate Amount Tax Rate Amount Tax Rate Federal statutory rate $ ) % $ ) % $ ) % Permanent differences )% )% )% State taxes ) % ) % — % Research and development credit ) % ) % ) % Valuation allowance )% )% )% Other )% )% )% ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective income tax rate $ — % $ — % $ — % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of significant components of deferred taxes	December 31, 2016 2015 Assets Liabilities Assets Liabilities Current: Accrued Expenses $ $ — $ $ — Other — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Subtotal — — Valuation allowance ) — ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net current deferred taxes $ $ $ $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long Term: Net operating loss carryforwards $ $ — $ $ — Capital loss carryforward — — — Research & development credit — — Capitalized research and development — — — Amortization — — Stock options and warrants — — Fixed assets — ) — ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Subtotal ) ) Valuation allowance ) ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total long-term deferred taxes $ $ ) $ $ ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net deferred tax assets/(liabilities) $ — $ — $ — $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of changes to the valuation allowance	Valuation allowance at December 31, 2014 $ Additions for 2015 Change in tax rates ​ ​ ​ ​ ​ Valuation allowance at December 31, 2015 Additions for 2016 Change in tax rates — ​ ​ ​ ​ ​ Valuation allowance at December 31, 2016 $ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Quarterly Financial Informati31

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information (Unaudited)
Summary of quarterly financial information	Quarter Ended December 31, September 30, June 30, March 31, Revenue $ — $ — $ — $ — Loss from operations $ ) $ ) $ ) $ ) Interest income $ $ $ $ Net loss and comprehensive loss $ ) $ ) $ ) $ ) Basic and diluted net loss per common share $ ) $ ) $ ) $ ) Weighted-average basic and diluted common shares outstanding Quarter Ended December 31, September 30, June 30, March 31, Revenue $ — $ — $ — $ — Loss from continuing operations $ ) $ ) $ ) $ ) Other income $ $ $ $ Net loss $ ) $ ) $ ) $ ) Basic and diluted net loss per common share $ ) $ ) $ ) $ ) Weighted-average basic and diluted common shares outstanding

Background (Details)

Background (Details) - USD ($)	Sep. 13, 2016	Mar. 03, 2016	Feb. 10, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Public Offering
Net Proceeds from Initial Public Offering				$ 246,489,901
Accumulated deficit				141,562,324	$ 58,550,520
Cash and Cash Equivalents, at Carrying Value				$ 240,429,839	$ 62,251,860	$ 3,119,713
Class B-1 Preferred Stock
Public Offering
Shares issued (in shares)					1,011,721	809,385
Shares converted (in shares)			3,278,938
Class B-2 Preferred Stock
Public Offering
Shares converted (in shares)			326,557
Class C Preferred Stock
Public Offering
Shares issued (in shares)					1,102,945	1,135,084
Shares converted (in shares)			2,365,020
Net proceeds from issuance of common stock					$ 5,000,020	$ 4,500,034
Class D Preferred Stock
Public Offering
Shares issued (in shares)					3,093,092
Shares converted (in shares)			3,105,000
Net proceeds from issuance of common stock					$ 64,787,549
Common Stock | IPO
Public Offering
Shares issued (in shares)			4,750,000	5,277,941
Share price (in dollars per share)			$ 20
Net Proceeds from Initial Public Offering			$ 88,350,000
Shares converted (in shares)				8,695,640
Common Stock | Over-Allotment Option
Public Offering
Shares issued (in shares)	637,500	527,941
Share price (in dollars per share)		$ 20
Net Proceeds from Initial Public Offering		$ 9,800,000
Common Stock | Follow-On Offering
Public Offering
Number of common shares to be sold under public offering	4,887,500
Shares issued (in shares)	4,597,645
Share price (in dollars per share)	$ 34.50
Net proceeds from issuance of common stock	$ 149,100,000
Common Stock | Stock Sold by Selling Stockholder
Public Offering
Shares issued (in shares)	289,855

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Property and Equipment (Details) - Office furniture and equipment	12 Months Ended
	Dec. 31, 2016
Minimum
Property and equipment, Useful life
Useful life	5 years
Maximum
Property and equipment, Useful life
Useful life	10 years

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Stock-Based Compensation (Details)	Dec. 31, 2016
Stock-Based Compensation
Forfeiture rate (as a percent)	0.00%

Summary of Significant Accoun35

Summary of Significant Accounting Policies - Restated Certificate of Incorporation (Details)	Feb. 01, 2016$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Feb. 17, 2016$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares
Restated Certificate of Incorporation
Common stock, shares authorized (in shares) | shares		100,000,000		22,080,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.0001		$ 0.0001
Deferred Initial Public Offering Costs
Deferred IPO related costs | $		$ 0		$ 1,624,040
Class B-1 Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares	3,278,938			3,278,938
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001		$ 0.0001
Stock split ratio	1.38
Class B-2 Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares	326,557
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001
Stock split ratio	1.38
Class C Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares	2,365,020			2,365,020
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001	0.0001		$ 0.0001
Stock split ratio	1.38
Class D Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares	3,105,000			3,105,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001		$ 0.0001
Stock split ratio	1.38
Undesignated Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares	1,000,000		10,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001		$ 0.0001
Common Stock
Restated Certificate of Incorporation
Common stock, shares authorized (in shares) | shares	30,000,000	100,000,000	100,000,000	22,080,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Stock split ratio	1.38
Preferred Stock | Class B-1 Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares				3,278,938
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.0001
Stock split ratio	1.38
Preferred Stock | Class B-2 Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares				326,557
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.0001
Stock split ratio	1.38
Preferred Stock | Class C Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares				2,365,020
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.0001
Stock split ratio	1.38
Preferred Stock | Class D Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares				3,105,000
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.0001
Stock split ratio	1.38
Preferred Stock | Undesignated Preferred Stock
Restated Certificate of Incorporation
Preferred stock, shares authorized (in shares) | shares		10,000,000		1,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.0001		$ 0.0001

Discontinued Operations (Detail

Discontinued Operations (Details)	12 Months Ended
	Dec. 31, 2014USD ($)	Jan. 30, 2014subsidiary
Discontinued Operations
Loss from discontinued operations, net of tax	$ (153,928)
Biolife Dallas | Disposed of by sale
Discontinued Operations
Number of wholly-owned subsidiaries sold | subsidiary		2
Loss from discontinued operations, net of tax	$ 200,000

Collaboration and License Agr37

Collaboration and License Agreements - Nationwide Children's Hospital (Details) - Nationwide Children's Hospital	Apr. 23, 2015USD ($)	Jan. 13, 2014USD ($)	May 31, 2015shares	Mar. 31, 2015shares	Aug. 31, 2014shares	Oct. 31, 2013USD ($)installment$ / sharesshares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	May 29, 2015USD ($)
Collaborative Arrangement
Collaboration and License Agreements
Minimum commitment to spend						$ 9,400,000
Minimum commitment to spend, period ( in years)						8 years
Development costs							$ 41,167,949	$ 9,890,947
Shares issued (in shares) | shares			3,802	34,463	86,725	331,053
Ownership percentage (as a percent)						3.00%
Aggregate potential future milestones						$ 125,000
Period following FDA approval of BLA to sell shares (in days)						30 days
Minimum ownership percentage of shares issued pursuant to the agreement (as a percent)						50.00%
Quarterly installments, number | installment						4
Market capitalization, threshold		$ 100,000,000				$ 50,000,000
Maximum period to file registration statement upon effective date (in days)						90 days
Maximum period to file registration statement upon written notice of dosing seventh patient (in days)		30 days
Amendment, consideration, payable		$ 50,000
Amendment, consideration, amount due on amendment date		20,000
Amendment, consideration, amount due within ten days of the first patient dosing		10,000
Amendment, consideration, amount due within ten days of the second patient dosing		10,000
Amendment, consideration, amount due within ten days of the fourth patient dosing		$ 10,000
Amendment, consideration, expensed	$ 100,000
License patent expiration period (in years)						10 years
Market capitalization, achieved											$ 100,000,000
Termination, notice period (in months)						6 months
Termination, event of a material uncured breach, notice period (in days)						30 days
Research and development expenses
Collaboration and License Agreements
Fair value of shares granted										$ 345,447
Research and development expenses | Collaborative Arrangement
Collaboration and License Agreements
Licensing costs reimbursed							$ 504,866	570,299	$ 341,482
Patent costs									83,163
Fair value of shares granted								$ 473,164	$ 214,298
Class B-1 Preferred Stock | Collaborative Arrangement
Collaboration and License Agreements
Ratio of the per share sale price to the price per share of preferred stock sold in Class B Financing						2
Share price (in dollars per share) | $ / shares						$ 2.47

Collaboration and License Agr38

Collaboration and License Agreements - REGENXBIO Inc. License (Details) - Collaborative Arrangement - ReGenX - USD ($)	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Mar. 21, 2014
Collaboration and License Agreements
Up-front payment, agreed-upon amount					$ 2,000,000
Up-front payment, paid	$ 1,000,000	$ 1,000,000
Aggregate potential future milestones					$ 12,250,000
Research and development expenses
Collaboration and License Agreements
Milestone payment			$ 0	$ 250,000
Maintenance fee			$ 50,000	$ 50,000

Collaboration and License Agr39

Collaboration and License Agreements - Asklepios Biopharmaceutical, Inc. License (Details) - Collaborative Arrangement - Asklepios Biopharmaceutical, Inc. - USD ($)	May 29, 2015	Dec. 31, 2016	Dec. 31, 2015
Collaboration and License Agreements
Up-front payment, agreed-upon amount	$ 1,000,000
Up-front payment, portion payable within 30 days of the effective date	300,000
Up-front payment, portion payable within 30 days following dosing of the first patient	300,000
Up-front payment, portion payable upon dosing of the ninth patient in a clinical trial	400,000
Aggregate potential future milestones	9,600,000
Annual maintenance fee	$ 50,000
Termination, notice period (in months)	6 months
Research and development expenses
Collaboration and License Agreements
Up-front payment, agreed-upon amount			$ 1,000,000
Maintenance fee		$ 50,000	$ 16,941

Property and Equipment, Net - T

Property and Equipment, Net - Tabular Disclosure (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Property and Equipment, Net
Property and equipment, gross	$ 24,277,037	$ 252,514
Less: accumulated depreciation	(76,455)	(16,924)
Property and equipment, net	24,200,582	235,590
Non-cash capital expenditures	4,871,547
Office furniture, equipment and leasehold improvements
Property and Equipment, Net
Property and equipment, gross	1,115,209	252,514
Construction in progress
Property and Equipment, Net
Property and equipment, gross	$ 23,161,828	$ 0

Property and Equipment, Net - D

Property and Equipment, Net - Depreciation Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property and Equipment, Net
Depreciation expense	$ 64,630	$ 13,463	$ 3,350

Property and Equipment, Net - C

Property and Equipment, Net - Construction in Progress (Details)	12 Months Ended
	Dec. 31, 2016USD ($)
Property and Equipment, Net
Accrued construction in progress	$ 2,978,498
Construction in progress
Property and Equipment, Net
Increase in construction in progress	$ 23,161,828

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Accrued Expenses
Accrued manufacturing development costs	$ 7,167,430	$ 513,606
Accrued payroll, bonus and deferred compensation	3,841,171	761,556
Accrued construction in progress	2,978,498
Accrued consulting	1,204,601
Accrued clinical trial costs	388,935	93,621
Accrued professional fees	382,874	348,165
Accrued severance	167,065	153,846
Other	663,429	566,223
Accrued expenses	$ 16,794,003	$ 2,437,017

Accrued Indemnification Oblig44

Accrued Indemnification Obligation (Details) - USD ($)	Jan. 28, 2014	Jan. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accrued Indemnification Obligation
Accrued indemnification obligation			$ 4,452,500	$ 4,080,500
Restricted Stock | Member of Board of Directors
Accrued Indemnification Obligation
Shares granted (in shares)	2,334,391	2,334,391
Share price (in dollars per share)	$ 1.51
Aggregate fair value					$ 3,535,419
Tax indemnification | Member of Board of Directors
Accrued Indemnification Obligation
Indemnification term (in years)			6 years
Accrued indemnification obligation			$ 4,452,500	$ 4,080,500

Capitalization - Stock Split (D

Capitalization - Stock Split (Details)	Feb. 01, 2016
Common Stock
Capitalization
Stock split ratio	1.38
Class B-1 Preferred Stock
Capitalization
Stock split ratio	1.38
Class B-1 Preferred Stock | Preferred Stock
Capitalization
Stock split ratio	1.38
Class B-2 Preferred Stock
Capitalization
Stock split ratio	1.38
Class B-2 Preferred Stock | Preferred Stock
Capitalization
Stock split ratio	1.38
Class C Preferred Stock
Capitalization
Stock split ratio	1.38
Class C Preferred Stock | Preferred Stock
Capitalization
Stock split ratio	1.38
Class D Preferred Stock
Capitalization
Stock split ratio	1.38
Class D Preferred Stock | Preferred Stock
Capitalization
Stock split ratio	1.38

Capitalization - Capital Stock

Capitalization - Capital Stock Authorized and Par Value (Details) - $ / shares	Dec. 31, 2016	Feb. 17, 2016	Feb. 01, 2016	Dec. 31, 2015
Common stock
Common stock, shares authorized (in shares)	100,000,000			22,080,000
Common stock, par value (in dollars per share)	$ 0.0001			$ 0.0001
Common stock, shares issued (in shares)	27,700,054			6,817,093
Common stock, shares outstanding (in shares)	27,700,054			6,817,093
Undesignated Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)		10,000,000	1,000,000
Preferred stock, par value (in dollars per share)		$ 0.0001	$ 0.0001
Class B-1 Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)			3,278,938	3,278,938
Preferred stock, par value (in dollars per share)	$ 0.0001		$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)	0			3,237,528
Preferred stock, shares outstanding (in shares)	0			3,237,528
Class B-2 Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)			326,557
Preferred stock, par value (in dollars per share)			$ 0.0001
Class C Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)			2,365,020	2,365,020
Preferred stock, par value (in dollars per share)	$ 0.0001		$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)	0			2,365,020
Preferred stock, shares outstanding (in shares)	0			2,365,020
Class D Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)			3,105,000	3,105,000
Preferred stock, par value (in dollars per share)	$ 0.0001		$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)	0			3,093,092
Preferred stock, shares outstanding (in shares)	0			3,093,092
Common Stock
Common stock
Common stock, shares authorized (in shares)	100,000,000	100,000,000	30,000,000	22,080,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares issued (in shares)	27,700,054
Common stock, shares outstanding (in shares)	27,700,054
Preferred Stock | Undesignated Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)	10,000,000			1,000,000
Preferred stock, par value (in dollars per share)	$ 0.0001			$ 0.0001
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Preferred Stock | Class B-1 Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)				3,278,938
Preferred stock, par value (in dollars per share)				$ 0.0001
Preferred Stock | Class B-2 Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)				326,557
Preferred stock, par value (in dollars per share)				$ 0.0001
Preferred Stock | Class C Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)				2,365,020
Preferred stock, par value (in dollars per share)				$ 0.0001
Preferred Stock | Class D Preferred Stock
Preferred stock
Preferred stock, shares authorized (in shares)				3,105,000
Preferred stock, par value (in dollars per share)				$ 0.0001

Capitalization - Exchange Agree

Capitalization - Exchange Agreements (Details)	Feb. 27, 2014shares	Feb. 18, 2014shares	Jan. 30, 2014agreementshares	Dec. 31, 2014USD ($)
Capitalization
Deemed preferred dividend on common stock | $				$ 866,569
JDH Investment Management, John Carbona & West Summit
Capitalization
Deemed preferred dividend on common stock | $				387,098
JDH Investment Management
Capitalization
Exchange Agreements, number | agreement			3
White Rock Capital Partners, LP and NRM
Capitalization
Deemed preferred dividend on common stock | $				$ 479,471
Common Stock | White Rock Capital Partners, LP
Capitalization
Shares exchanged (in shares)		303,518
Common Stock | Investor | JDH Investment Management
Capitalization
Shares exchanged (in shares)			202,347
Common Stock | Investor | West Summit
Capitalization
Shares exchanged (in shares)			202,347
Common Stock | Beneficial Owner | NRM
Capitalization
Shares exchanged (in shares)	303,518
Class B-1 Preferred Stock | Preferred Stock | White Rock Capital Partners, LP
Capitalization
Shares exchanged (in shares)		303,518
Class B-1 Preferred Stock | Preferred Stock | Investor | JDH Investment Management
Capitalization
Shares exchanged (in shares)			202,347
Class B-1 Preferred Stock | Preferred Stock | Investor | West Summit
Capitalization
Shares exchanged (in shares)			202,347
Class B-1 Preferred Stock | Preferred Stock | Beneficial Owner | NRM
Capitalization
Shares exchanged (in shares)	303,518
Chief Executive Officer | Common Stock | John Carbona
Capitalization
Shares exchanged (in shares)			202,347
Chief Executive Officer | Class B-1 Preferred Stock | Preferred Stock | John Carbona
Capitalization
Shares exchanged (in shares)			202,347

Capitalization - Liquidation Ev

Capitalization - Liquidation Event (Details) - Preferred Stock	Dec. 31, 2016$ / shares
Class C Preferred Stock
Preferred stock
Liquidation preference per share (in dollars per share)	$ 4.2299
Class D Preferred Stock
Preferred stock
Liquidation preference per share (in dollars per share)	21.0145
Class B-1 Preferred Stock
Preferred stock
Liquidation preference per share (in dollars per share)	2.471
Class B-2 Preferred Stock
Preferred stock
Liquidation preference per share (in dollars per share)	$ 2.572

Capitalization - Conversion (De

Capitalization - Conversion (Details) - Preferred Stock	Dec. 31, 2016shares
Class B-1 Preferred Stock
Preferred Stock
Common stock shares for each preferred stock share (in shares)	1
Class B-2 Preferred Stock
Preferred Stock
Common stock shares for each preferred stock share (in shares)	1
Class C Preferred Stock
Preferred Stock
Common stock shares for each preferred stock share (in shares)	1
Class D Preferred Stock
Preferred Stock
Common stock shares for each preferred stock share (in shares)	1

Capitalization - Class B-1 and

Capitalization - Class B-1 and B-2 Preferred Stock (Details) - USD ($)	May 04, 2015	Mar. 07, 2014	Jan. 30, 2014	Dec. 31, 2015	Dec. 31, 2014
PBM Capital Investments, LLC | Class B-2 Warrant and Class B-2 Milestone Warrant
Capitalization
Warrants, term (in years)	10 years
PBM Capital Investments, LLC | Class B Note
Capitalization
Face amount			$ 500,000
Stock option, exercise price (in dollars per share)			$ 2.47
Class B-1 Preferred Stock
Capitalization
Shares issued (in shares)				1,011,721	809,385
Preferred Stock | Class B-1 Preferred Stock
Capitalization
Certification period (in days)			10 days
Preferred Stock | Class B-1 Preferred Stock | PBM Capital Investments, LLC
Capitalization
Option to purchase shares, number (in shares)			809,385
Stock option, exercise price (in dollars per share)			$ 2.47
Shares issued (in shares)		1,011,721	1,011,721
Share price (in dollars per share)		$ 2.47
Cash proceeds		$ 2,000,000
Preferred Stock | Class B-1 Preferred Stock | PBM Capital Investments, LLC | Class B-2 Milestone Warrant
Capitalization
Cash proceeds	$ 2,500,000
Preferred Stock | Class B-1 Preferred Stock | PBM Capital Investments, LLC | Class B Note
Capitalization
Share price (in dollars per share)			$ 2.47
Preferred Stock | Class B-2 Preferred Stock | PBM Capital Investments, LLC
Capitalization
Warrant to purchase shares, number (in shares)			163,278
Preferred Stock | Class B-2 Preferred Stock | PBM Capital Investments, LLC | Class B-2 Warrant
Capitalization
Warrant to purchase shares, number (in shares)		130,623	130,623
Warrants, exercise price (in dollars per share)		$ 2.57	$ 2.57
Preferred Stock | Class B-2 Preferred Stock | PBM Capital Investments, LLC | Class B Note | Class B-2 Warrant
Capitalization
Warrant to purchase shares, number (in shares)		32,652
Warrants, exercise price (in dollars per share)		$ 2.57

Capitalization - Class C Prefer

Capitalization - Class C Preferred Stock (Details) - USD ($)	Apr. 15, 2015	Mar. 17, 2015	Aug. 12, 2014	Aug. 11, 2014	Jun. 20, 2014	Dec. 31, 2015	Dec. 31, 2014
Deerfield Private Design Fund III | Deerfield Convertible Note
Capitalization
Original principal amount converted					$ 500,000
Class C Preferred Stock
Capitalization
Shares issued (in shares)						1,102,945	1,135,084
Class C Preferred Stock | Deerfield Convertible Note
Capitalization
Share issued upon debt conversion (in shares)							126,991
Preferred Stock | Class C Preferred Stock | Deerfield Private Design Fund III and Roche Finance Ltd
Capitalization
Milestone period (in days)			15 days
Written notice period (in days)	5 days
Cash proceeds		$ 5,000,020
Preferred Stock | Class C Preferred Stock | Deerfield Private Design Fund III
Capitalization
Shares issued (in shares)			551,472	504,478
Share price (in dollars per share)			$ 4.53	$ 3.96
Conversion price (in dollars per share)					$ 3.96
Preferred Stock | Class C Preferred Stock | Deerfield Private Design Fund III | Deerfield Convertible Note
Capitalization
Share issued upon debt conversion (in shares)				126,991	126,991
Conversion price (in dollars per share)				$ 3.96
Preferred Stock | Class C Preferred Stock | Roche Finance Ltd
Capitalization
Shares issued (in shares)			551,472	630,606
Share price (in dollars per share)			$ 4.53	$ 3.96

Capitalization - Class D Prefer

Capitalization - Class D Preferred Stock Issuance (Details) - Class D Preferred Stock - USD ($)	Sep. 03, 2015	Dec. 31, 2015
Capitalization
Shares issued (in shares)		3,093,092
Preferred Stock
Capitalization
Shares issued (in shares)	3,093,092
Share price (in dollars per share)	$ 21.01
Cash proceeds	$ 64,787,549

Convertible Notes (Details)

Convertible Notes (Details) - USD ($)	Feb. 10, 2016	Aug. 12, 2014	Aug. 11, 2014	Jun. 20, 2014	Jun. 19, 2014	Mar. 07, 2014	Jan. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Convertible Notes
Proceeds from convertible notes										$ 1,000,000
Net Proceeds from Initial Public Offering								$ 246,489,901
Class B-1 Preferred Stock
Convertible Notes
Shares issued (in shares)									1,011,721	809,385
Shares converted (in shares)	3,278,938
Class B-2 Preferred Stock
Convertible Notes
Shares converted (in shares)	326,557
Class C Preferred Stock
Convertible Notes
Shares issued (in shares)									1,102,945	1,135,084
Shares converted (in shares)	2,365,020
PBM Capital Investments, LLC | Preferred Stock | Class B-1 Preferred Stock
Convertible Notes
Nonemployee stock option, exercise price (in dollars per share)							$ 2.47
Shares issued (in shares)						1,011,721	1,011,721
Share price (in dollars per share)						$ 2.47
PBM Capital Investments, LLC | Preferred Stock | Class B-2 Preferred Stock
Convertible Notes
Warrant to purchase shares, number (in shares)							163,278
PBM Capital Investments, LLC | Preferred Stock | Class B-2 Preferred Stock | Class B-2 Warrant
Convertible Notes
Warrant to purchase shares, number (in shares)						130,623	130,623
Warrants, exercise price (in dollars per share)						$ 2.57	$ 2.57
Deerfield Private Design Fund III | Preferred Stock | Class C Preferred Stock
Convertible Notes
Conversion price (in dollars per share)				$ 3.96
Shares issued (in shares)		551,472	504,478
Share price (in dollars per share)		$ 4.53	$ 3.96
Class B Note | Class B-1 Preferred Stock
Convertible Notes
Shares issued in conversion										202,345
Class B Note | PBM Capital Investments, LLC
Convertible Notes
Face amount							$ 500,000
Interest rate (as a percent)							8.00%
Minimum amount benchmark from issuance or sale of equity securities to be considered for conversion of debt							$ 500,000
Proceeds from convertible notes							500,000
Fair value of nonemployee stock option							$ 112,835
Nonemployee stock option, exercise price (in dollars per share)							$ 2.47
Nonemployee stock option, volatility rate (as a percent)							45.00%
Nonemployee stock option, expected term (in months)							1 month
Nonemployee stock option, dividend yield (as a percent)							0.00%
Nonemployee stock option, interest rate (as a percent)							0.40%
Class B Note | PBM Capital Investments, LLC | Interest expense
Convertible Notes
Unamortized debt discount										$ 112,835
Class B Note | PBM Capital Investments, LLC | Class B-1 Preferred Stock
Convertible Notes
Shares converted (in shares)	3,278,938
Class B Note | PBM Capital Investments, LLC | Class B-2 Preferred Stock
Convertible Notes
Shares converted (in shares)	326,557
Class B Note | PBM Capital Investments, LLC | Preferred Stock | Class B-1 Preferred Stock
Convertible Notes
Conversion price (in dollars per share)						$ 2.47	$ 2.47
Fair value of contingent milestone shares							$ 0
Contingent milestone shares, exercise price (in dollars per share)							$ 2.40
Unamortized debt discount							$ 112,835
Share price (in dollars per share)							$ 2.47
Shares issued in conversion						202,345
Class B Note | PBM Capital Investments, LLC | Preferred Stock | Class B-2 Preferred Stock | Class B-2 Warrant
Convertible Notes
Warrant to purchase shares, number (in shares)						32,652
Warrants, exercise price (in dollars per share)						$ 2.57
Deerfield Convertible Note | Class C Preferred Stock
Convertible Notes
Shares issued in conversion										126,991
Deerfield Convertible Note | Deerfield Private Design Fund III
Convertible Notes
Face amount					$ 500,000
Interest rate (as a percent)					5.00%
Origination fee (as a percent)					2.50%
Fair value of debt					$ 500,000
Deerfield Convertible Note | Deerfield Private Design Fund III | Class C Preferred Stock
Convertible Notes
Shares converted (in shares)	2,365,020
Deerfield Convertible Note | Deerfield Private Design Fund III | Preferred Stock | Class C Preferred Stock
Convertible Notes
Conversion price (in dollars per share)			$ 3.96
Shares issued in conversion			126,991	126,991
IPO | Common Stock
Convertible Notes
Shares issued (in shares)	4,750,000							5,277,941
Share price (in dollars per share)	$ 20
Net Proceeds from Initial Public Offering	$ 88,350,000
Shares converted (in shares)								8,695,640
IPO | Class B Note | PBM Capital Investments, LLC | Common Stock
Convertible Notes
Shares issued (in shares)	4,750,000
Share price (in dollars per share)	$ 20
Net Proceeds from Initial Public Offering	$ 88,350,000
IPO | Deerfield Convertible Note | Deerfield Private Design Fund III | Common Stock
Convertible Notes
Shares issued (in shares)	4,750,000
Share price (in dollars per share)	$ 20
Net Proceeds from Initial Public Offering	$ 88,350,000

Stock-based Compensation - Gene

Stock-based Compensation - General Information (Details) - shares	Feb. 10, 2016	Aug. 31, 2016	Dec. 31, 2016
2016 Equity Incentive Plan
Stock-based Compensation
Common stock that may be issued pursuant to stock awards (in shares)	4,339,451
Common stock that may be issued pursuant to stock awards, new shares (in shares)	2,400,000
Annual automatic increase percentage (as a percent)	4.00%
Plan expiration period (in years)			10 years
Expiration period (in years)			3 months
Minimum | 2016 Equity Incentive Plan
Stock-based Compensation
Vesting period (in years)			2 years
Maximum | 2016 Equity Incentive Plan
Stock-based Compensation
Vesting period (in years)			4 years
Employee Stock Options | 2016 Equity Incentive Plan
Stock-based Compensation
Common stock that may be issued pursuant to stock awards (in shares)	8,678,902
Restricted Stock Units
Stock-based Compensation
Shares granted (in shares)		57,500	57,500
Vesting period (in years)			3 years

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Details) - Employee Stock Options - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Number of Shares
Outstanding at the beginning of the period (in shares)	1,748,875
Granted (in shares)	973,638
Exercised (in shares)	(84,127)
Cancelled or forfeited (in shares)	(61,275)
Outstanding at the end of the period (in shares)	2,577,111	1,748,875
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 15.04
Granted (in dollars per share)	33.10
Exercised (in dollars per share)	5.11
Cancelled or forfeited (in dollars per share)	22.19
Outstanding at the end of the period (in dollars per share)	$ 22.01	$ 15.04
Weighted Average
Remaining Contractual Life (Years)	8 years 9 months 15 days	9 years 4 months 17 days
Aggregate Intrinsic Value (in dollars)	$ 66,466,245	$ 8,224,947
Exercisable and Vested and Expected to Vest
Number of Shares - exercisable (in shares)	704,111	168,360
Weighted Average Exercise Price - exercisable (in dollars per share)	$ 14.86	$ 2.47
Remaining Contractual Life (Years) - exercisable	8 years 5 months 1 day	8 years 4 months 28 days
Aggregate Intrinsic Value - exercisable (in dollars)	$ 23,146,606	$ 2,907,260
Number of Shares - vested and expected to vest (in shares)	2,577,111	1,668,837
Weighted Average Exercise Price - vested and expected to vest (in dollars per share)	$ 22.01	$ 15.64
Remaining Contractual Life (Years) - vested and expected to vest	8 years 9 months 15 days	9 years 5 months 1 day
Aggregate Intrinsic Value - vested and expected to vest (in dollars)	$ 66,466,245	$ 6,842,807

Stock-based Compensation - St56

Stock-based Compensation - Stock Options Exercised (Details) - Employee Stock Options - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock-based Compensation
Common stock, future grant (in shares)	1,704,840
Total intrinsic value of option exercised	$ 3,449,227	$ 3,565,436	$ 0

Stock-based Compensation - Unre

Stock-based Compensation - Unrecognized Stock-based Compensation Expense (Details) - Employee Stock Options	12 Months Ended
	Dec. 31, 2016USD ($)
Unrecognized stock-based compensation expense
Unrecognized stock-based compensation expense	$ 20,583,606
Unrecognized stock-based compensation expense, weighted average recognition period (in years)	1 year 4 months 24 days

Stock-based Compensation - Aggr

Stock-based Compensation - Aggregate Stock-based Compensation Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Aggregate stock-based compensation expense
Aggregate stock-based compensation expense	$ 15,656,372	$ 5,250,217	$ 416,624
Research and development expenses
Aggregate stock-based compensation expense
Aggregate stock-based compensation expense	5,988,231	1,293,841	179,641
General and administrative expenses
Aggregate stock-based compensation expense
Aggregate stock-based compensation expense	$ 9,668,141	$ 3,956,376	$ 236,983

Stock-based Compensation - Weig

Stock-based Compensation - Weighted Average Grant Date Fair Value (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Stock Options
Weighted Average Grant Date Fair Value
Weighted-average grant date fair value of options granted during the period (in dollars per share)	$ 24.50	$ 16.44	$ 1.47

Stock-based Compensation - We60

Stock-based Compensation - Weighted-average Assumptions (Details) - Employee Stock Options	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted-average fair value assumptions
Expected volatility (as a percent)	91.84%	90.00%	86.94%
Risk-free interest rate (as a percent)	1.45%	1.57%	1.16%
Expected term (in years)	6 years 29 days	6 years 29 days	4 years 2 months 9 days
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Stock Units - General Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock based Compensation
Stock-based compensation expense	$ 15,656,372	$ 5,250,217	$ 416,624
Restricted Stock Units
Stock based Compensation
Stock-based compensation expense	758,637
Unrecognized compensation cost	$ 1,248,113
Unrecognized stock-based compensation expense, weighted average recognition period (in years)	1 year 2 months 12 days

Stock-based Compensation - Re62

Stock-based Compensation - Restricted Stock Units - Activity (Details) - Restricted Stock Units - $ / shares	1 Months Ended	12 Months Ended
	Aug. 31, 2016	Dec. 31, 2016
Number of Shares
Granted (in shares)	57,500	57,500
Outstanding at the end of the period (in shares)		57,500
Weighted Average Grant Date Fair Value Per Share
Granted (in dollars per share)		$ 34.90
Outstanding at the end of the period (in dollars per share)		$ 34.90

Stock-based Compensation - Re63

Stock-based Compensation - Restricted Stock Units - Additional Information (Details)	12 Months Ended
	Dec. 31, 2016
Restricted Stock Units
Stock based Compensation
Vesting period (in years)	3 years

Stock-based Compensation - Re64

Stock-based Compensation - Restricted Stock Granted to Non-Employees - Consulting Agreement (Details) - Member of Board of Directors - Restricted Stock - shares	Jan. 28, 2014	Jan. 31, 2014
Stock based Compensation
Shares granted (in shares)	2,334,391	2,334,391
Shares vested (in shares)		583,597
Shares vesting upon grant
Stock based Compensation
Vesting percentage (as a percent)		25.00%
Shares vesting on second anniversary
Stock based Compensation
Vesting percentage (as a percent)		25.00%
Shares vesting on third anniversary
Stock based Compensation
Vesting percentage (as a percent)		25.00%
Shares vesting on fourth anniversary
Stock based Compensation
Vesting percentage (as a percent)		25.00%

Stock-based Compensation - Re65

Stock-based Compensation - Restricted Stock Granted to Non-Employees - Employment Agreement (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of Shares
Aggregate stock-based compensation expense		$ 15,656,372	$ 5,250,217	$ 416,624
Non-Employee | Restricted Stock
Number of Shares
Outstanding at the beginning of the period (in shares)	1,750,794	1,750,794
Shares vested (in shares)		1,750,794
Outstanding at the end of the period (in shares)			1,750,794
Employee | Restricted Stock
Number of Shares
Shares granted (in shares)	1,750,794
Research and development expenses
Number of Shares
Aggregate stock-based compensation expense		$ 5,988,231	$ 1,293,841	179,641
Research and development expenses | Employee | Restricted Stock
Number of Shares
Aggregate stock-based compensation expense		$ 10,370,762	$ 19,322,275	$ 5,749,791

Stock-based Compensation - Warr

Stock-based Compensation - Warrants Granted to Non-Employees - General Information (Details) - First Warrant - Pavilion	Aug. 05, 2014$ / sharesshares
Warrant information
Warrants, aggregate shares (in shares)	138,000
Warrants, exercise price (in dollars per share) | $ / shares	$ 2.47
Shares exercisable immediately upon issuance (in shares)	69,000
Shares exercisable upon share purchase (in shares)	34,500
Shares exercisable on January 26, 2015 (in shares)	34,500

Stock-based Compensation - Wa67

Stock-based Compensation - Warrants Granted to Non-Employees - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 05, 2014
Warrant information
Aggregate stock-based compensation expense	$ 15,656,372	$ 5,250,217	$ 416,624
Stock warrants exercised (in shares)	20,771	138,000
Proceeds from exercise of stock warrants	$ 53,350	$ 341,000
Research and development expenses
Warrant information
Aggregate stock-based compensation expense	5,988,231	1,293,841	$ 179,641
First Warrant | Pavilion
Warrant information
Grant date fair value	146,000
Warrants, exercise price (in dollars per share)				$ 2.47
First Warrant | Pavilion | Research and development expenses
Warrant information
Aggregate stock-based compensation expense	$ 0	$ 358,637
Common Stock | Non-Employee
Warrant information
Stock warrants vested ( in shares)	305,775	326,556
Stock warrants outstanding (in shares)	305,775	326,556
Warrants, exercise price (in dollars per share)	$ 2.57	$ 2.57

Net Loss Per Common Share - Dil

Net Loss Per Common Share - Dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive securities not included:
Antidilutive securities	2,940,386	3,826,225	2,628,774
Employee Stock Options
Antidilutive securities not included:
Antidilutive securities	2,577,111	1,748,875	473,202
Stock warrants
Antidilutive securities not included:
Antidilutive securities	305,775	326,556	404,778
Restricted Stock Units
Antidilutive securities not included:
Antidilutive securities	57,500
Restricted Stock
Antidilutive securities not included:
Antidilutive securities		1,750,794	1,750,794

Net Loss Per Common Share - Cal

Net Loss Per Common Share - Calculation (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Loss from continuing operations									$ (83,011,804)	$ (38,473,844)	$ (15,551,848)
Less: deemed preferred dividends on common stock											(866,569)
Net loss attributable from continuing operations to common stockholders									(83,011,804)	(38,473,844)	(16,418,417)
Loss from discontinued operations											(153,928)
Net loss attributable to common stockholders									$ (83,011,804)	$ (38,473,844)	$ (16,572,345)
Denominator:
Weighted-average basic and diluted common shares (in shares)	27,678,348	24,166,113	23,013,838	16,774,718	7,226,122	7,504,148	7,030,976	6,895,185	22,647,583	7,087,618	6,916,404
Basic and diluted net loss per common share from continuing operations									$ (3.67)	$ (5.43)	$ (2.37)
Basic and diluted net loss per common share from discontinued operations											(0.02)
Basic and diluted net loss per common share (in dollars per share)	$ (0.92)	$ (0.87)	$ (0.68)	$ (1.24)	$ (1.82)	$ (1.32)	$ (1.41)	$ (0.79)	$ (3.67)	$ (5.43)	$ (2.39)

Separation Agreement - Severanc

Separation Agreement - Severance and Vacation Pay (Details) - USD ($)	Apr. 22, 2015	May 31, 2015	Dec. 31, 2015	Dec. 31, 2016
Separation Agreement
Accrued severance			$ 153,846	$ 167,065
Chief Executive Officer
Separation Agreement
Accrued severance and vacation	$ 535,000
Accrued severance	500,000
Accrued vacation	$ 35,000
Severance payment period (in months)	12 months	12 months
Lump sum payment percentage (as a percent)		50.00%
Lump sum payment period after termination (in days)		30 days
Equal installments payment percentage (as a percent)		50.00%
Equal installments payment period after termination (in months)		6 months
General and administrative expenses | Chief Executive Officer
Separation Agreement
Severance benefit and vacation pay charge			$ 535,000

Separation Agreement - Unvested

Separation Agreement - Unvested Stock Options (Details) - USD ($)	Apr. 22, 2015	Dec. 31, 2015	Dec. 31, 2016
Separation Agreement
Accrued severance		$ 153,846	$ 167,065
Chief Executive Officer
Separation Agreement
Accrued severance	$ 500,000
Chief Executive Officer | Employee Stock Options
Separation Agreement
Accelerated vesting (in shares)	53,820
Chief Executive Officer | Employee Stock Options | General and administrative expenses
Separation Agreement
Accelerated vesting charge (in dollars)		$ 503,502

Commitments and Contingencies -

Commitments and Contingencies - Operating Lease - General Information (Details) - ft²	Mar. 31, 2016	Mar. 31, 2014
Office space in Dallas, Texas
Operating Leases
Approximate size of office space (in square feet)		2,418
Facility for corporate headquarters Bannockburn, Illinois
Operating Leases
Approximate size of office space (in square feet)		15,668
Facility in Columbus, Ohio
Operating Leases
Approximate size of office space (in square feet)		1,318
Office and warehouse space in Libertyville, Illinois
Operating Leases
Approximate size of office space (in square feet)	48,529

Commitments and Contingencies73

Commitments and Contingencies - Operating Lease - Future Minimum Lease Payments (Details)	Dec. 31, 2016USD ($)
Operating Leases
2,017	$ 507,823
2,018	660,572
2,019	674,850
2,020	689,289
2,021	703,894
Thereafter	2,514,993
Total	$ 5,751,421

Commitments and Contingencies74

Commitments and Contingencies - Operating Lease - Rent Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leases
Rent expense	$ 283,892	$ 91,959	$ 38,824

Commitments and Contingencies75

Commitments and Contingencies - Guarantees and Indemnifications (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Accrued Indemnification Obligation
Accrued indemnification obligation	$ 4,452,500	$ 4,080,500
Member of Board of Directors | Tax indemnification
Accrued Indemnification Obligation
Accrued indemnification obligation	$ 4,452,500	$ 4,080,500

Commitments and Contingencies76

Commitments and Contingencies - Litigation (Details) - Sophia's Cure Foundation - Nationwide Children's Hospital - Breach of donation agreement - USD ($)	Sep. 08, 2016	Dec. 31, 2012
Litigation
Gift received under donation agreement		$ 550,000
Monetary damages sought	$ 500,000,000

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of difference between federal statutory rate and effective income tax rate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective income tax rate, Amount
Federal statutory rate	$ (28,224,013)	$ (13,081,107)	$ (5,339,964)
Permanent differences	3,990,847	6,077,476	1,110,536
State taxes	(2,453,391)	(1,275,192)
Research and development credit	(8,890,651)	(219,873)	(42,958)
Valuation allowance	35,502,582	8,471,572	4,271,416
Other	$ 74,626	$ 27,124	$ 970
Tax Rate (as a percent)
Federal statutory rate (as a percent)	34.00%	34.00%	34.00%
Permanent differences (as a percent)	(4.73%)	(15.80%)	(7.06%)
State taxes (as a percent)	2.97%	3.31%	0.00%
Research and development credit (as a percent)	10.55%	0.57%	0.27%
Valuation allowance (as a percent)	(42.70%)	(21.38%)	(27.20%)
Other (as a percent)	(0.09%)	(0.70%)	(0.01%)
Effective income tax rate (as a percent)	0.00%	0.00%	0.00%

Income Taxes - Deferred taxes (

Income Taxes - Deferred taxes (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Current, Assets
Accrued Expenses	$ 2,994,611	$ 1,553,014
Other	45,194	26,252
Subtotal	3,039,805	1,579,266
Valuation allowance	(3,039,805)	(1,579,266)
Net current deferred taxes	0	0
Current, Liabilities
Net current deferred taxes	0	0
Long Term, Assets
Net operating loss carryforwards	13,063,481	8,785,945
Capital loss carryforward	113,010
Research & development credit	13,733,227	262,831
Capitalized research and development	11,796,974
Amortization	1,422,863	1,438,858
Stock options and warrants	6,263,828	1,856,913
Subtotal	46,393,383	12,344,547
Valuation allowance	(46,376,496)	(12,334,453)
Total long-term deferred taxes	16,887	10,094
Long Term, Liabilities
Fixed assets	(16,887)	(10,094)
Subtotal	(16,887)	(10,094)
Total long-term deferred taxes	$ (16,887)	$ (10,094)

Income Taxes - Operating loss c

Income Taxes - Operating loss carryforwards (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Operating loss carryforwards
Percentage of valuation allowance equal to deferred tax asset	100.00%
Operating loss carryforward available for immediate use	$ 25,590,114
Research and development tax credit
Operating loss carryforwards
Research and development tax credit carryforwards	13,733,227	$ 262,831
Federal
Operating loss carryforwards
Net operating loss carryforwards	$ 34,551,469	$ 16,525,413

Income Taxes - Valuation Allowa

Income Taxes - Valuation Allowance (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Taxes
Valuation allowance	$ 13,913,719	$ 5,441,262
Additions	35,502,582	8,192,872
Change in tax rates		279,585
Valuation allowance	$ 419,416,301	$ 13,913,719

Related Party Transactions (Det

Related Party Transactions (Details)	Mar. 07, 2014USD ($)	Jan. 31, 2014USD ($)shares	Dec. 31, 2016stockholder
Member of Board of Directors | Consulting agreement
Related Party Transactions
Legal fees | $		$ 33,088
Member of Board of Directors | Common Stock | Consulting agreement
Related Party Transactions
Number of restricted shares granted | shares		2,334,391
Member of Board of Directors | Dr. David Genecov | Shares of Biolife Cell Bank Management, LLC Transaction
Related Party Transactions
Shares sold (in shares) | shares		1,000
Member of Board of Directors | Dr. David Genecov | Shares of Biolife Cell Bank Intellectual Property, LLC Transaction
Related Party Transactions
Shares sold (in shares) | shares		1,000
PBM | Services Agreement
Related Party Transactions
Agreed amount for services | $	$ 205,000
Initial term (in months)	18 months
PBM | Services Agreement | General and administrative expenses
Related Party Transactions
Recognized service expense | $	$ 103,180
ReGenX
Related Party Transactions
Number of stockholders affiliated with related party | stockholder			1
Beneficial Owner
Related Party Transactions
Number of stockholders affiliated with director | stockholder			2
Beneficial Owner | Common Stock
Related Party Transactions
Beneficial ownership interests held by two stockholders (as a percent)			11.80%

Retirement Plan (Details)

Retirement Plan (Details)	12 Months Ended
	Dec. 31, 2016USD ($)
Simple IRA Plan
Retirement Plan
Contributions expenses	$ 145,921

Quarterly Financial Informati83

Quarterly Financial Information (Unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly financial information
Loss from operations	$ (25,547,384)	$ (21,180,396)	$ (15,797,787)	$ (20,889,002)	$ (13,165,526)	$ (10,029,427)	$ (9,923,360)	$ (5,454,659)	$ (83,414,569)	$ (38,572,972)	$ (15,420,321)
Interest income	172,453	98,588	78,829	52,895					402,765	14,570	(131,527)
Other income					4,719	88,769	4,185	1,455		84,558
Net loss	(25,374,931)	(21,081,808)	(15,718,958)	(20,836,107)	$ (13,160,807)	$ (9,940,658)	$ (9,919,175)	$ (5,453,204)	(83,011,804)	(38,473,844)	(15,705,776)
Comprehensive loss	$ (25,374,931)	$ (21,081,808)	$ (15,718,958)	$ (20,836,107)					$ (83,011,804)	$ (38,473,844)	$ (15,705,776)
Basic and diluted net loss per common share (in dollars per share)	$ (0.92)	$ (0.87)	$ (0.68)	$ (1.24)	$ (1.82)	$ (1.32)	$ (1.41)	$ (0.79)	$ (3.67)	$ (5.43)	$ (2.39)
Weighted-average basic and diluted common shares outstanding (in shares)	27,678,348	24,166,113	23,013,838	16,774,718	7,226,122	7,504,148	7,030,976	6,895,185	22,647,583	7,087,618	6,916,404