Consolidated Statements of Stockholders' Equity - 6 months ended Jun. 30, 2015 - USD ($) $ in Thousands	Total	Common stock	APIC	Accumulated Deficit
Balance at December 31, 2014 at Dec. 31, 2014	$ 249,198	$ 8	$ 460,179	$ (210,989)
Balance (in shares) at Dec. 31, 2014	79,811,769	79,811,769
Increase (Decrease) in Stockholders' Equity
Net loss	$ (26,362)			(26,362)
Stock-based compensation	19,295		19,295
Issuance of warrants and change in fair value of unvested warrants relating to marketing agreements	(480)		(480)
Net exercise of warrants to purchase common stock (in shares)		959,676
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes	4,596		4,596
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes (in shares)		1,482,858
Balance at June 30, 2015 at Jun. 30, 2015	$ 246,247	$ 8	$ 483,590	$ (237,351)
Balance (in shares) at Jun. 30, 2015	82,254,303	82,254,303