Avexis (AVXS) 10-Q 10 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 10, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	AveXis, Inc.
Entity Central Index Key	1,652,923
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		27,676,288
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 263,642,069	$ 62,251,860
Prepaid expenses and other current assets	3,813,545	909,629
Total current assets	267,455,614	63,161,489
Property and equipment, net	16,831,697	235,590
Other long-term assets	516,395	1,687,212
Total assets	284,803,706	65,084,291
Current liabilities:
Accounts payable	3,748,718	359,787
Accrued expenses	9,616,624	2,437,017
Accrued indemnification obligation	4,216,000	4,080,500
Total current liabilities	17,581,342	6,877,304
Total liabilities	17,581,342	6,877,304
Redeemable common stock; par value $0.0001 per share, no shares issued and outstanding at September 30, 2016; 456,043 shares issued and outstanding at December 31, 2015		1,032,909
Stockholders' equity:
Common stock; par value $0.0001 per share, 100,000,000 shares authorized, 27,645,108 shares issued and outstanding at September 30, 2016; 22,080,000 shares authorized, 6,817,093 shares issued and outstanding at December 31, 2015	2,765	682
Additional paid-in capital	383,406,992	115,723,046
Accumulated deficit	(116,187,393)	(58,550,520)
Total stockholder's equity	267,222,364	57,174,078
Total liabilities, redeemable common stock and stockholders' equity	$ 284,803,706	65,084,291
Class D Preferred Stock
Stockholders' equity:
Preferred stock		309
Class C Preferred Stock
Stockholders' equity:
Preferred stock		237
Class B-1 Preferred Stock
Stockholders' equity:
Preferred stock		$ 324

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Sep. 30, 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	27,645,108	6,817,093
Common stock, shares outstanding	27,645,108	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)	0	3,105,000
Preferred stock, shares issued (in shares)	0	3,093,092
Preferred stock, shares outstanding (in shares)	0	3,093,092
Preferred stock, aggregate liquidation preference (in dollars)		$ 64,999,782
Class C Preferred Stock
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	0	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)		$ 5,003,492
Class B-2 Preferred Stock
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	0	326,557
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
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)	0	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
Undesignated Preferred Stock
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Consolidated Statements of Operations and Comprehensive Loss
Revenue	$ 0	$ 0	$ 0	$ 0
Operating expenses:
General and administrative	7,082,683	3,740,077	17,324,863	6,651,233
Research and development	14,097,713	6,289,350	40,542,323	18,756,214
Total operating expenses	21,180,396	10,029,427	57,867,186	25,407,447
Loss from operations	(21,180,396)	(10,029,427)	(57,867,186)	(25,407,447)
Interest income	98,588	88,769	230,313	94,410
Net loss	(21,081,808)	(9,940,658)	(57,636,873)	(25,313,037)
Comprehensive loss	$ (21,081,808)	$ (9,940,658)	$ (57,636,873)	$ (25,313,037)
Basic and diluted net loss per common share (in dollars per share)	$ (0.87)	$ (1.32)	$ (2.75)	$ (3.59)
Weighted-average basic and diluted common shares outstanding (in shares)	24,166,113	7,504,148	20,958,421	7,042,977

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net loss	$ (57,636,873)	$ (25,313,037)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	32,827	5,820
Stock-based compensation	22,712,933	2,719,702
Non-cash research and development		15,296,515
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,907,823)	(90,502)
Accounts payable	1,051,266	501,844
Other long-term assets	(847,924)	(73,124)
Accrued expenses	4,261,747	646,882
Accrued indemnification obligation	135,500
Net cash used in operating activities	(33,198,347)	(6,305,900)
Cash flows from investing activities
Capital expenditures	(11,702,171)	(76,920)
Net cash used in investing activities	(11,702,171)	(76,920)
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	247,228,422
Payments of deferred offering costs	(1,198,220)
Proceeds from exercise of stock options	218,525	341,000
Proceeds from exercise of stock warrants	42,000	341,000
Net cash provided by financing activities	246,290,727	72,969,569
Net increase in cash and cash equivalents	201,390,209	66,586,749
Cash and cash equivalents, beginning of period	62,251,860	3,119,713
Cash and cash equivalents, end of period	263,642,069	69,706,462
Supplemental Cash Flow Information
Cash paid for interest		439
Supplemental Disclosure of Non-cash Investing and Financing Activities
Purchases of property and equipment in accounts payable and accrued liabilities	4,926,762
Deferred issuance costs for underwritten offering in accounts payable and accrued liabilities	$ 727,367
Deferred issuance costs for planned initial public offering in accrued expenses		322,914
Class B Preferred Stock
Cash flows from financing activities
Proceeds from issuance of preferred stock		2,500,000
Class C Preferred Stock
Cash flows from financing activities
Proceeds from issuance of preferred stock		5,000,020
Class D Preferred Stock
Cash flows from financing activities
Proceeds from issuance of preferred stock		$ 64,787,549

Background

Background	9 Months Ended
	Sep. 30, 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. Initial Public Offering On February 17, 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 $88.4 million after deducting underwriting discounts and other estimated offering costs. 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, less underwriting discounts, resulting in net proceeds of approximately $9.8 million. Underwritten 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 and other offering expenses payable by the Company, 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	9 Months Ended
	Sep. 30, 2016
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial reporting and the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) and, therefore, do not include all information and footnote disclosures normally included in the annual consolidated financial statements. In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments of a normal recurring nature that are necessary for a fair statement of the results for the interim periods presented. Interim results are not necessarily indicative of results for a full year. The December 31, 2015 condensed consolidated balance sheet data contained within this Form 10-Q was derived from audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 (“Annual Report on Form 10-K”), but does not include all disclosures required by GAAP. Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies as of and for the nine months ended September 30, 2016, as compared with the significant accounting policies described in the Company’s Annual Report on Form 10-K. Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. 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 reported amounts of revenues, if any, and expenses during the reporting period. Actual results could differ from those estimates. In the Company’s opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair presentation of the Company’s financial position, results of operations and cash flows for the interim periods presented. 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 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, 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. The ASU will be 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 is evaluating the adoption of this ASU, but has not determined 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, 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 the ASU, 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. The ASU is effective for annual and interim periods beginning after December 15, 2015, with early adoption permitted. The Company has adopted this ASU, which did not have a material effect on the Company’s consolidated financial statements. In November 2014, the FASB issued ASU No. 2014-16, Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity (“ASU 2014-16”). The guidance requires an entity to determine the nature of the host contract by considering all stated and implied substantive terms and features of the hybrid financial instrument, weighing each term and feature on the basis of the relevant facts and circumstances (commonly referred to as the whole-instrument approach). ASU 2014-16 applies to all entities and is effective for annual periods beginning after December 15, 2015, and interim periods thereafter. Early adoption is permitted. The Company has adopted this ASU which did not have a material effect on the Company’s consolidated financial statements. In November 2015, the FASB issued Accounting Standards Update 2015-17, Balance Sheet Classification of Deferred Taxes. 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. The new guidance will be 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 adoption, but has not determined the effects it may have on the Company’s consolidated financial statements. In February 2015, the FASB issued ASU No. 2015-2, Consolidation (Topic 810): Amendments to the Consolidation Analysis, which provides clarification regarding the guidance surrounding consolidation of certain legal entities. This guidance is effective for annual and interim periods beginning after December 15, 2015. The Company has adopted this ASU, which did not have a material effect 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 is evaluating the adoption of ASU 2016-09, but has not determined the effects it may have on the Company’s consolidated financial statements.

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2016
Property and Equipment, Net
Property and Equipment, Net	3. Property and Equipment, Net Property and equipment, net, consists of the following: September 30, December 31, Office furniture and equipment $ $ Construction in progress — Property and equipment, gross Less: accumulated depreciation ) ) Property and equipment, net $ $ Depreciation expense was $5,711 and $2,951 for the three months ended September 30, 2016 and 2015, respectively, and $32,827 and $5,820 for the nine months ended September 30, 2016 and 2015, respectively. Construction in progress increased by $16,533,947 for the nine months ended September 30, 2016. This is primarily due to procurement of manufacturing equipment and construction within the Company’s Libertyville, Illinois manufacturing facility.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2016
Accrued Expenses
Accrued Expenses	4. Accrued Expenses Accrued expenses consist of the following: September 30, December 31, Accrued manufacturing development costs $ $ Accrued payroll, bonus and deferred compensation Accrued construction in process — Accrued professional fees Accrued issuance costs for planned initial public offering — Accrued employee expenses — Accrued clinical trial costs Accrued license maintenance fees Accrued severance Accrued franchise tax — Deferred rent — Other Accrued expenses $ $

Accrued Indemnification Obligat

Accrued Indemnification Obligation	9 Months Ended
	Sep. 30, 2016
Accrued Indemnification Obligation
Accrued Indemnification Obligation	5. 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 6) 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 (“IRS”) 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, 2015 and September 30, 2016. 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 accrued $4,216,000 and $4,080,500 at September 30, 2016 and December 31, 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 expense through September 30, 2016. The Company expects to pay this entire amount in 2016.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2016
Stock-Based Compensation
Stock-Based Compensation	6. Stock-Based Compensation 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 may be issued pursuant to stock awards under the 2016 Plan is 4,339,451 shares, which is 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 following table summarizes stock option activity under the Plans for the nine months ended September 30, 2016: Weighted Average Number of Weighted Remaining Aggregate Outstanding at December 31, 2015 $ $ Granted $ Exercised $ Cancelled or forfeited $ Outstanding at September 30, 2016 $ $ Exercisable at September 30, 2016 $ Exercisable and expected to vest at September 30, 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 September 30, 2016 and December 31, 2015. For the nine months ended September 30, 2016 and 2015, the total number of stock options exercised was 33,625 and 138,000, respectively, resulting in total proceeds of $218,525 and $341,000, respectively. As of September 30, 2016 and December 31, 2015, there was $21,706,937 and $12,942,684, respectively, of unrecognized stock-based compensation expense related to stock option awards that is expected to be recognized over a weighted-average period of 1.5 and 1.9 years, respectively. The Company has recorded total stock-based compensation expense related to the issuance of stock option awards under the Plans in the consolidated statements of operations and comprehensive loss as follows: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Research and development $ $ $ $ General and administrative $ $ $ Stock Options Granted to Employees The weighted-average grant date fair value of options granted during the three months ended September 30, 2016 and 2015 was $27.87 and $18.07, respectively, and for the nine months ended September 30, 2016 and 2015 was $23.98 and $16.29, respectively, on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Expected volatility % % % % Risk-free interest rate % % % % Expected terms (in years) Expected dividend yield % % % % Restricted Stock Units As of September 30, 2016 and December 31, 2015, there were 57,500 and 0, respectively, unvested restricted stock units granted to employees. During both the three and nine months ended September 30, 2016, no restricted stock units vested, and the Company recognized stock-based compensation expense of $703,232 during both the three and nine months ended September 30, 2016. At September 30, 2016, there was $1,361,018 of unrecognized compensation cost related to unvested restricted stock units that will be recognized as expense over a weighted-average period of 1.4 years. A summary of the status of the Company’s restricted stock units at September 30, 2016 and of changes in restricted stock units outstanding under the 2016 Plan for the nine months ended September 30, 2016 is as follows: Weighted Average Grant Date Number Fair Value of Shares Per Share Outstanding at December 31, 2015 — $ — Granted Vested — — Forfeited and cancelled — — Outstanding at September 30, 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 AICPA Practice Guide, with the assistance of independent third party valuations, and approved by the Company’s Board of Directors. Prior to the IPO, 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. Refer to the Annual Report on Form 10-K for details of each valuation. 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 in the nine months ended September 30, 2016, in research and development expenses. This compares to $8,690,824 of stock compensation expense recognized related to the grant in the nine months ended September 30, 2015.

Net Loss Per Common Share

Net Loss Per Common Share	9 Months Ended
	Sep. 30, 2016
Net Loss Per Common Share
Net Loss Per Common Share	7. 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, unvested restricted common stock and unvested restricted stock units. 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 three and nine months ended September 30, 2016 and 2015, the following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding because the effect would be anti-dilutive: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Stock options 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: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Numerator: Net loss and comprehensive loss $ ) $ ) $ ) $ ) Denominator: Weighted-average basic and diluted common shares Basic and diluted net loss per common share $ ) $ ) $ ) $ )

Separation Agreement

Separation Agreement	9 Months Ended
	Sep. 30, 2016
Separation Agreement
Separation Agreement	8. Separation Agreement On April 22, 2015, the Company’s prior chief executive officer (the “Prior CEO”), ceased to be an employee of the Company. In connection with the termination of his employment, the Company agreed to pay the Prior CEO 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, under the terms of the separation agreement, in the event the Prior CEO were to resign, or be removed from, his service on the Company’s Board, then (i) 50% of the then unpaid portion of Severance due to the Prior CEO would be paid to him 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 to the Prior CEO would be 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 June 2015, the Prior CEO’s service on the Board terminated. 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 the Prior CEO 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. At December 31, 2015, the Company had $153,846 related to the Severance recorded as an accrued liability, which was paid in the first quarter of 2016. Therefore there is no remaining obligation as of September 30, 2016.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies
Commitments and Contingencies	9. Commitments and Contingencies Operating Lease In March 2016, the Company entered into a lease agreement, which expires in September 2026, for approximately 48,529 square feet of warehouse and office space Libertyville, Illinois. A portion of the warehouse space will house the Company’s manufacturing operations. 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 are as follows: Year ending December 31, 2016 $ 2017 2018 2019 2020 Thereafter Total $ In July 2015, the Company entered into a lease agreement for 4,795 square feet of office space for its headquarters in Bannockburn, Illinois. In August 2016, the Company amended the lease agreement to relocate the leased premises to 15,688 square feet in the same building and terminate the existing lease with respect to the 4,795 square feet at no cost to the Company. The amended lease term expires May 2024. The amended lease agreement provides for annual escalation in rent payments during the lease term and provides the Company with a one-time right to terminate the lease effective as of the last day of the sixty-fifth 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 are as follows: Year ending December 31, 2016 $ 2017 2018 2019 2020 Thereafter Total $ License Agreements The Company has entered into license agreements, which 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 $4,216,000 and $4,080,500 at September 30, 2016 and December 31, 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. 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 September 30, 2016 and December 31, 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 Company’s exclusive license agreement with NCH. 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, and the court has yet to rule on this motion. 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.

Taxes

Taxes	9 Months Ended
	Sep. 30, 2016
Taxes
Taxes	10. Taxes Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are provided if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, including its net operating losses. Based on its history of operating losses, the Company believes that it is more likely than not that the benefit of its deferred tax assets will not be realized. Accordingly, the Company has provided a full valuation allowance for deferred tax assets as of September 30, 2016 and December 31, 2015.

Summary of Significant Accoun16

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial reporting and the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) and, therefore, do not include all information and footnote disclosures normally included in the annual consolidated financial statements. In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments of a normal recurring nature that are necessary for a fair statement of the results for the interim periods presented. Interim results are not necessarily indicative of results for a full year. The December 31, 2015 condensed consolidated balance sheet data contained within this Form 10-Q was derived from audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 (“Annual Report on Form 10-K”), but does not include all disclosures required by GAAP.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. 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 reported amounts of revenues, if any, and expenses during the reporting period. Actual results could differ from those estimates. In the Company’s opinion, the accompanying unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair presentation of the Company’s financial position, results of operations and cash flows for the interim periods presented.
Recent Accounting Pronouncements	Recent Accounting Pronouncements 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, 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. The ASU will be 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 is evaluating the adoption of this ASU, but has not determined 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, 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 the ASU, 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. The ASU is effective for annual and interim periods beginning after December 15, 2015, with early adoption permitted. The Company has adopted this ASU, which did not have a material effect on the Company’s consolidated financial statements. In November 2014, the FASB issued ASU No. 2014-16, Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity (“ASU 2014-16”). The guidance requires an entity to determine the nature of the host contract by considering all stated and implied substantive terms and features of the hybrid financial instrument, weighing each term and feature on the basis of the relevant facts and circumstances (commonly referred to as the whole-instrument approach). ASU 2014-16 applies to all entities and is effective for annual periods beginning after December 15, 2015, and interim periods thereafter. Early adoption is permitted. The Company has adopted this ASU which did not have a material effect on the Company’s consolidated financial statements. In November 2015, the FASB issued Accounting Standards Update 2015-17, Balance Sheet Classification of Deferred Taxes. 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. The new guidance will be 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 adoption, but has not determined the effects it may have on the Company’s consolidated financial statements. In February 2015, the FASB issued ASU No. 2015-2, Consolidation (Topic 810): Amendments to the Consolidation Analysis, which provides clarification regarding the guidance surrounding consolidation of certain legal entities. This guidance is effective for annual and interim periods beginning after December 15, 2015. The Company has adopted this ASU, which did not have a material effect 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 is evaluating the adoption of ASU 2016-09, but has not determined the effects it may have on the Company’s consolidated financial statements.

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2016
Property and Equipment, Net
Summary of property and equipment, net	September 30, December 31, Office furniture and equipment $ $ Construction in progress — Property and equipment, gross Less: accumulated depreciation ) ) Property and equipment, net $ $

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2016
Accrued Expenses
Schedule of accrued expenses	September 30, December 31, Accrued manufacturing development costs $ $ Accrued payroll, bonus and deferred compensation Accrued construction in process — Accrued professional fees Accrued issuance costs for planned initial public offering — Accrued employee expenses — Accrued clinical trial costs Accrued license maintenance fees Accrued severance Accrued franchise tax — Deferred rent — Other Accrued expenses $ $

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2016
Stock-Based Compensation
Summary of Company's stock option activity	Weighted Average Number of Weighted Remaining Aggregate Outstanding at December 31, 2015 $ $ Granted $ Exercised $ Cancelled or forfeited $ Outstanding at September 30, 2016 $ $ Exercisable at September 30, 2016 $ Exercisable and expected to vest at September 30, 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 September 30, 2016 and December 31, 2015.
Summary of aggregate stock-based compensation recorded in the consolidated statements of operations and comprehensive loss	Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Research and development $ $ $ $ General and administrative $ $ $
Summary of Company's grant date fair value and assumptions used in determining fair value of stock options	Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Expected volatility % % % % Risk-free interest rate % % % % Expected terms (in years) Expected dividend yield % % % %
Summary of Company's restricted stock units activity	Weighted Average Grant Date Number Fair Value of Shares Per Share Outstanding at December 31, 2015 — $ — Granted Vested — — Forfeited and cancelled — — Outstanding at September 30, 2016 $

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2016
Net Loss Per Common Share
Potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding	Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Stock options Stock warrants Unvested restricted stock units — — Unvested restricted common stock — —
Summary of the basic and diluted net loss per common share	Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Numerator: Net loss and comprehensive loss $ ) $ ) $ ) $ ) Denominator: Weighted-average basic and diluted common shares Basic and diluted net loss per common share $ ) $ ) $ ) $ )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Office and warehouse space in Libertyville, Illinois
Future minimum lease payments	Year ending December 31, 2016 $ 2017 2018 2019 2020 Thereafter Total $
Office space in Bannockburn, Illinois
Future minimum lease payments	Year ending December 31, 2016 $ 2017 2018 2019 2020 Thereafter Total $

Background (Details)

Background (Details) - USD ($)	Sep. 13, 2016	Mar. 03, 2016	Feb. 17, 2016	Sep. 30, 2016
Public Offering
Net proceeds from issuance of common stock				$ 247,228,422
Class B-1 Preferred Stock
Public Offering
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 converted (in shares)			2,365,020
Class D Preferred Stock
Public Offering
Shares converted (in shares)			3,105,000
Common Stock | IPO
Public Offering
Shares issued (in shares)			4,750,000
Share price (in dollars per share)			$ 20
Net proceeds			$ 88,400,000
Common Stock | Over-Allotment Option
Public Offering
Shares issued (in shares)	637,500	527,941
Share price (in dollars per share)		$ 20
Net proceeds		$ 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 Accoun23

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

Property and Equipment, Net - T

Property and Equipment, Net - Tabular Disclosure (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Property and Equipment, Net
Property and equipment, gross	$ 16,881,448	$ 252,514
Less: accumulated depreciation	(49,751)	(16,924)
Property and equipment, net	16,831,697	235,590
Office furniture and equipment
Property and Equipment, Net
Property and equipment, gross	347,501	$ 252,514
Construction in progress
Property and Equipment, Net
Property and equipment, gross	$ 16,533,947

Property and Equipment, Net - D

Property and Equipment, Net - Depreciation Expense (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property and Equipment, Net
Depreciation expense	$ 5,711	$ 2,951	$ 32,827	$ 5,820

Property and Equipment, Net - C

Property and Equipment, Net - Construction in Progress (Details)	9 Months Ended
	Sep. 30, 2016USD ($)
Construction in progress
Property and Equipment, Net
Increase in construction in progress	$ 16,533,947

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Accrued Expenses
Accrued manufacturing development costs	$ 2,321,708	$ 513,606
Accrued payroll, bonus and deferred compensation	2,545,909	761,556
Accrued construction in process	2,877,251
Accrued professional fees	909,343	348,165
Accrued issuance costs for planned initial public offering		371,043
Accrued employee expenses	45,380
Accrued clinical trial costs	111,938	93,621
Accrued license maintenance fees	46,187	68,311
Accrued severance	128,020	153,846
Accrued franchise tax	129,168
Deferred rent	113,661
Other	388,059	126,869
Accrued expenses	$ 9,616,624	$ 2,437,017

Accrued Indemnification Oblig28

Accrued Indemnification Obligation (Details) - USD ($)	Jan. 28, 2014	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Accrued Indemnification Obligation
Accrued indemnification obligation		$ 4,216,000	$ 4,080,500
Restricted Stock | Director
Accrued Indemnification Obligation
Shares granted (in shares)	2,334,391
Share price (in dollars per share)	$ 1.51
Aggregate fair value				$ 3,535,419
Tax indemnification | Director
Accrued Indemnification Obligation
Indemnification term (in years)		6 years
Accrued indemnification obligation		$ 4,216,000	$ 4,080,500

Stock-Based Compensation - Gene

Stock-Based Compensation - General Information (Details) - 2016 Equity Incentive Plan - shares	Feb. 10, 2016	Jan. 01, 2026
Stock-Based Compensation
Plan expiration period (in years)	10 years
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%
Forecast
Stock-Based Compensation
Common stock that may be issued pursuant to stock awards (in shares)		8,678,902

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - Employee Stock Options - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Number of Shares
Outstanding at the beginning of the period (in shares)	1,748,877
Granted (in shares)	877,640
Exercised (in shares)	33,625	138,000
Cancelled or forfeited (in shares)	25,875
Outstanding at the end of the period (in shares)	2,567,017		1,748,877
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 15.04
Granted (in dollars per share)	31.41
Exercised (in dollars per share)	6.50
Cancelled or forfeited (in dollars per share)	18.17
Outstanding at the end of the period (in dollars per share)	$ 20.51		$ 15.04
Weighted Average
Remaining Contractual Life (Years)	8 years 11 months 12 days		9 years 4 months 17 days
Aggregate Intrinsic Value (in dollars)	$ 54,745,699		$ 8,224,947
Exercisable and Vested and Expected to Vest
Number of Shares - exercisable (in shares)	635,347
Weighted Average Exercise Price - exercisable (in dollars per share)	$ 13.54
Number of Shares - vested and expected to vest (in shares)	2,502,817
Weighted Average Exercise Price - vested and expected to vest (in dollars per share)	$ 21.17
Remaining Contractual Life (Years) - vested and expected to vest	8 years 11 months 23 days
Aggregate Intrinsic Value - vested and expected to vest (in dollars)	$ 50,563,537

Stock-Based Compensation - St31

Stock-Based Compensation - Stock Options Exercised (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Stock-Based Compensation
Proceeds from exercise of stock options	$ 218,525	$ 341,000
Employee Stock Options
Stock-Based Compensation
Exercised (in shares)	33,625	138,000
Proceeds from exercise of stock options	$ 218,525	$ 341,000

Stock-Based Compensation - Unre

Stock-Based Compensation - Unrecognized Stock-based Compensation Expense (Details) - Employee Stock Options - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Stock-Based Compensation
Unrecognized stock-based compensation expense	$ 21,706,937	$ 12,942,684
Unrecognized stock-based compensation expense, weighted average recognition period (in years)	1 year 6 months	1 year 10 months 24 days

Stock-Based Compensation - Aggr

Stock-Based Compensation - Aggregate Stock-based Compensation Expense (Details) - Employee Stock Options - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Stock-Based Compensation
Aggregate stock-based compensation expense	$ 4,623,081	$ 1,848,624	$ 22,010,557	$ 2,719,702
Research and development expenses
Stock-Based Compensation
Aggregate stock-based compensation expense	2,006,547	359,881	14,757,305	411,257
General and administrative expenses
Stock-Based Compensation
Aggregate stock-based compensation expense	$ 2,616,534	$ 1,488,743	$ 7,253,252	$ 2,308,445

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Grant Date Fair Value (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Stock Options
Stock-Based Compensation
Weighted-average grant date fair value of options granted during the period (in dollars per share)	$ 27.87	$ 18.07	$ 23.98	$ 16.29

Stock-Based Compensation - We35

Stock-Based Compensation - Weighted-average Assumptions (Details) - Employee Stock Options	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Stock-Based Compensation
Expected volatility (as a percent)	97.82%	80.80%	92.46%	80.80%
Risk-free interest rate (as a percent)	1.10%	1.89%	1.42%	1.89%
Expected term (in years)	6 years 29 days	6 years 29 days	6 years 29 days	6 years 29 days
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units - General Information (Details) - Unvested restricted stock units - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Stock-Based Compensation
Unvested restricted stock units granted to employees (in shares)	57,500	57,500	0
Shares vested (in shares)	0	0
Stock-based compensation expense	$ 703,232	$ 703,232
Unrecognized compensation cost	$ 1,361,018	$ 1,361,018
Unrecognized stock-based compensation expense, weighted average recognition period (in years)		1 year 4 months 24 days

Stock-Based Compensation - Re37

Stock-Based Compensation - Restricted Stock Units - Activity (Details) - Unvested restricted stock units - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Number of Shares
Outstanding at the beginning of the period (in shares)		0
Granted (in shares)		57,500
Vested (in shares)	0	0
Outstanding at the end of the period (in shares)	57,500	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	$ 34.90

Stock-Based Compensation - Re38

Stock-Based Compensation - Restricted Stock Units - Additional Information (Details)	9 Months Ended
	Sep. 30, 2016
Unvested restricted stock units
Stock-Based Compensation
Vesting period (in years)	3 years

Stock-Based Compensation - Re39

Stock-Based Compensation - Restricted Stock Granted to Non-Employees - Consulting Agreement (Details) - Director - Restricted Stock	Jan. 28, 2014shares
Stock-Based Compensation
Shares granted (in shares)	2,334,391
Shares vested (in shares)	583,597
Vesting period (in years)	4 years
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 - Re40

Stock-Based Compensation - Restricted Stock Granted to Non-Employees - Employment Agreement (Details) - Employee - Restricted Stock - USD ($)	1 Months Ended	9 Months Ended
	Jan. 31, 2016	Sep. 30, 2016	Sep. 30, 2015
Stock-Based Compensation
Shares granted (in shares)	1,750,794
Shares vested (in shares)	1,750,794
Research and development expenses
Stock-Based Compensation
Aggregate stock-based compensation expense		$ 10,370,762	$ 8,690,824

Net Loss Per Common Share - Dil

Net Loss Per Common Share - Dilutive Securities (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Antidilutive securities not included:
Antidilutive securities	2,934,737	3,660,868	2,934,737	3,660,868
Employee Stock Options
Antidilutive securities not included:
Antidilutive securities	2,567,017	1,583,521	2,567,017	1,583,521
Stock warrants
Antidilutive securities not included:
Antidilutive securities	310,220	326,553	310,220	326,553
Unvested restricted stock units
Antidilutive securities not included:
Antidilutive securities	57,500		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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net loss	$ (21,081,808)	$ (9,940,658)	$ (57,636,873)	$ (25,313,037)
Denominator:
Weighted-average basic and diluted common shares (in shares)	24,166,113	7,504,148	20,958,421	7,042,977
Basic and diluted net loss per common share (in dollars per share)	$ (0.87)	$ (1.32)	$ (2.75)	$ (3.59)

Separation Agreement - Severanc

Separation Agreement - Severance and Vacation Pay (Details) - USD ($)	Apr. 22, 2015	May 31, 2015	Dec. 31, 2015	Sep. 30, 2016
Separation Agreement
Accrued severance			$ 153,846	$ 128,020
Chief Executive Officer
Separation Agreement
Accrued severance and vacation	$ 535,000
Accrued severance	500,000		153,846	$ 0
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	Sep. 30, 2016
Separation Agreement
Accrued severance		$ 153,846	$ 128,020
Chief Executive Officer
Separation Agreement
Accrued severance	$ 500,000	153,846	$ 0
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)	1 Months Ended
	Aug. 31, 2016USD ($)ft²	Jul. 31, 2016ft²	Mar. 31, 2016ft²	Jul. 31, 2015ft²
Office and warehouse space in Libertyville, Illinois
Operating Leases
Approximate size of office space (in square feet)			48,529
Office space in Bannockburn, Illinois
Operating Leases
Approximate size of office space (in square feet)	15,688	4,795		4,795
Cost of operating leases amendment | $	$ 0

Commitments and Contingencies46

Commitments and Contingencies - Operating Lease - Future Minimum Lease Payments (Details)	Sep. 30, 2016USD ($)
Office and warehouse space in Libertyville, Illinois
Operating Leases
2,016	$ 62,481
2,017	251,486
2,018	257,774
2,019	264,218
2,020	270,823
Thereafter	1,693,216
Total	2,799,998
Office space in Bannockburn, Illinois
Operating Leases
2,016	20,379
2,017	260,903
2,018	403,451
2,019	411,285
2,020	419,119
Thereafter	1,490,419
Total	$ 3,005,556

Commitments and Contingencies47

Commitments and Contingencies - Guarantees and Indemnifications (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Accrued Indemnification Obligation
Accrued indemnification obligation	$ 4,216,000	$ 4,080,500
Director | Tax indemnification
Accrued Indemnification Obligation
Accrued indemnification obligation	$ 4,216,000	$ 4,080,500

Commitments and Contingencies48

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