Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Receivables from the Exercises of Options	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2016	$ 209,824	$ 4	$ 1,006,344		$ (13)	$ (796,511)
Beginning Balance (in shares) at Dec. 31, 2016	36,826,010	36,826,010
Stock-based compensation	$ 29,764		29,764
Exercises of stock options/issuances of RSUs	$ 706		717	$ (11)
Exercises of stock options/issuances of RSUs (in shares)	33,468	137,268
Unrealized gain on available-for-sale securities	$ (37)				(37)
Net loss	(72,865)					(72,865)
Ending Balance at Mar. 31, 2017	$ 167,392	$ 4	$ 1,036,825	$ (11)	$ (50)	$ (869,376)
Ending Balance (in shares) at Mar. 31, 2017	36,963,278	36,963,278