Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Contributed Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning Balance, amount at Dec. 31, 2013	$ 41,517	$ 42	$ 75,937	$ (34,484)	$ 22
Beginning Balance (shares) at Dec. 31, 2013		41,650,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(30,933)			(30,933)
Issuance of common stock	44,875	$ 3	44,872
Issuance of common stock (shares)		2,678,000
Exercise of options and warrants	923		923
Exercise of options and warrants (shares)		312,000
Unrealized loss on available-for-sale securities	(15)				(15)
Foreign currency translation adjustment	0
Equity-based compensation	9,624		9,624
Ending Balance, amount at Dec. 31, 2014	65,991	$ 45	131,356	(65,417)	7
Ending Balance (shares) at Dec. 31, 2014		44,640,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(45,498)			(45,498)
Issuance of common stock	103,351	$ 6	103,345
Issuance of common stock (shares)		6,426,000
Exercise of options and warrants	$ 805		805
Exercise of options and warrants (shares)	124,884	125,000
Unrealized loss on available-for-sale securities	$ (20)				(20)
Foreign currency translation adjustment	1				1
Equity-based compensation	8,388		8,388
Ending Balance, amount at Dec. 31, 2015	133,018	$ 51	243,894	(110,915)	(12)
Ending Balance (shares) at Dec. 31, 2015		51,191,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(66,374)			(66,374)
Exercise of options and warrants	$ 1,497	$ 1	1,496
Exercise of options and warrants (shares)	158,743	314,000
Short swing profits (net of costs)	$ 866		866
Issuance of common stock under employee purchase plan	226		226
Issuance of common stock under employee purchase plan (shares)		11,000
Unrealized loss on available-for-sale securities	(64)				(64)
Foreign currency translation adjustment	(128)				(128)
Equity-based compensation	8,775		8,775
Ending Balance, amount at Dec. 31, 2016	$ 77,816	$ 52	$ 255,257	$ (177,289)	$ (204)
Ending Balance (shares) at Dec. 31, 2016		51,516,000