Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Other Comprehensive Loss	Accumulated Deficit	Initial Public Offering	Initial Public Offering Common Stock	Initial Public Offering Additional Paid-in Capital	Private Placement	Private Placement Common Stock	Private Placement Additional Paid-in Capital	Accredited Investors	Accredited Investors Common Stock	Accredited Investors Additional Paid-in Capital	Brink Biologics Inc Spinout	Brink Biologics Inc Spinout Accumulated Deficit	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Series C Convertible Preferred Stock	Common Class A	Common Class B
Beginning Balance, Shares at Dec. 31, 2012																	406,048			362,897
Beginning Balance, as adjusted at Dec. 31, 2012	$ (4,394)		$ 946		$ (5,341)															$ 1
Issuance of convertible preferred stock less issuance costs	511		511
Issuance of convertible preferred stock less issuance costs, Shares																		1,851
Conversion to Class A common stock, Shares																	(406,048)			406,048
Conversion of debt and payables to Class A common stock	950		950
Conversion of debt and payables to Class A common stock, Shares																				389,437
Exercise of Class B common stock	341		340																		$ 1
Exercise of Class B common stock, Shares																					1,681,099
Stock-based compensation expense	884		884
Net loss, as adjusted (See Note 15) | As Adjusted	(2,047)				(2,047)
Net loss, as adjusted (See Note 15)	(2,047)
Ending Balance, as adjusted at Dec. 31, 2013	(3,755)		3,631		(7,388)															$ 1	$ 1
Ending Balance, Shares at Dec. 31, 2013																		1,851		1,158,382	1,681,099
Issuance of convertible preferred stock less issuance costs	6,701		6,701
Issuance of convertible preferred stock less issuance costs, Shares																			5,754,984
Conversion of debt and payables to Class A common stock	1,339		1,339
Conversion of debt and payables to Class A common stock, Shares																				1,522,799
Exercise of Class B common stock	1,185		1,185
Exercise of Class B common stock, Shares																					5,851,152
Stock-based compensation expense	562		562
Net loss, as adjusted (See Note 15) | As Adjusted	(6,185)
Net loss, as adjusted (See Note 15)	(6,185)				(6,185)
Ending Balance, as adjusted at Dec. 31, 2014	57,591		71,158		(13,573)															$ 6
Ending Balance, Shares at Dec. 31, 2014																				61,094,367
Issuance of restricted stock	227		227
Issuance of restricted stock, Shares																				129,605
Issuance of stock to placement agent, Shares																				3,087,324	763,151
Issuance of common stock less issuance costs	57,337		57,334																	$ 3
Issuance of common stock less issuance costs, Shares																				30,809,800
Conversion of Preferred B and C convertible preferred stock and Class B common stock			(1)																	$ 2	$ (1)
Conversion of Preferred B and C convertible preferred stock and Class B common stock, Shares																		(1,851)	(5,754,984)	23,553,284	(8,295,402)
Exercise of stock options	180		180
Exercise of stock options, Shares																				833,173
Ending Balance (As Adjusted) at Dec. 31, 2014	57,591
Net loss, as adjusted (See Note 15)	(117,470)
Beginning Balance, Shares at Dec. 31, 2014																				61,094,367
Beginning Balance, as adjusted at Dec. 31, 2014	57,591		71,158		(13,573)															$ 6
Net loss, as adjusted (See Note 15)	(160,110)
Beginning Balance, Shares at Dec. 31, 2014																				61,094,367
Beginning Balance, as adjusted at Dec. 31, 2014	57,591		71,158		(13,573)															$ 6
Conversion to Class A common stock		$ 7																		$ (7)
Conversion to Class A common stock, Shares		65,900,303																		(65,900,303)
Stock-based compensation expense	211,221		211,221
Net loss, as adjusted (See Note 15) | As Adjusted	(236,876)				(236,876)
Net loss, as adjusted (See Note 15)	(236,876)
Ending Balance, Shares at Dec. 31, 2015		81,311,686
Issuance of common stock less issuance costs						$ 221,475	$ 1	$ 221,474	$ 17,000		$ 17,000	$ 77,977		$ 77,977
Issuance of common stock less issuance costs, Shares							9,531,200			680,000			4,063,333
Exercise of stock options	878		877																	$ 1
Exercise of stock options, Shares		177,703																		949,396
Vesting of restricted stock units		485,150
Employee payroll taxes withheld related to vesting of restricted stock units	(2,415)		(2,415)
Employee payroll taxes withheld related to vesting of restricted stock units, Shares		(96,612)
Warrants issued in conjunction with Inex Bio purchase	5,170		5,170
Exercise of warrants	7,348		7,348
Exercise of warrants, Shares		570,609																		4,106,492
Repurchase of common stock	$ (4,798)		(4,798)
Repurchase of common stock, Shares	0																			(249,952)
Reclassification of warrant liability due to exercise	$ 1,543		1,543
Spinout of Brink Biologics, Inc.															$ 73	$ 73
Other comprehensive loss	(192)			$ (192)
Ending Balance (As Adjusted) at Dec. 31, 2015	355,995
Ending Balance at Dec. 31, 2015	355,995	$ 8	606,555	(192)	(250,376)
Net loss, as adjusted (See Note 15) | As Adjusted	9
Net loss, as adjusted (See Note 15) | As Adjusted	(26,822)
Net loss, as adjusted (See Note 15)	(26,822)
Ending Balance, Shares at Dec. 31, 2015		81,311,686
Ending Balance (As Adjusted) at Dec. 31, 2015	355,995
Ending Balance at Dec. 31, 2015	$ 355,995	$ 8	$ 606,555	$ (192)	$ (250,376)