Condensed Consolidated Statements of Stockholders' Equity - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Receivables from the Exercise of Options	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2014	$ 117,048	$ 3	$ 399,191	$ (835)	$ (95)	$ (281,216)
Beginning Balance (in shares) at Dec. 31, 2014	30,548,309	30,548,309
Stock-based compensation	$ 73,254		73,254
Exercises of stock options	$ 26,908		26,073	$ 835
Exercises of stock options (in shares)	720,253	720,253
Issuance of performance shares (in shares)		4,965
Issuance of common stock	$ 205,133		205,133
Issuance of common stock (in shares)		1,150,000
Unrealized gain on available for sale securities	63				63
Net loss	(177,565)					(177,565)
Ending Balance at Sep. 30, 2015	$ 244,841	$ 3	$ 703,651		$ (32)	$ (458,781)
Ending Balance (in shares) at Sep. 30, 2015	32,423,527	32,423,527