Consolidated Statements of Stockholders' Equity - 6 months ended Jun. 30, 2017 - USD ($) $ in Thousands	Total	Common stock	APIC	Accumulated Deficit
Beginning Balance at Dec. 31, 2016	$ 224,581	$ 9	$ 542,807	$ (318,235)
Balance (in shares) at Dec. 31, 2016	86,159,527	86,159,527
Increase (Decrease) in Stockholders' Equity
Net loss	$ (14,855)			(14,855)
Stock Issued During Period, Value, New Issues	17,398		17,398
Stock Issued During Period, Shares, New Issues		1,150,000
Stock-based compensation	13,303		13,303
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes	54,107	$ 1	54,106
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes (in shares)		10,265,698
Ending Balance at Jun. 30, 2017	$ 294,534	$ 10	$ 627,614	$ (333,090)
Balance (in shares) at Jun. 30, 2017	97,575,225	97,575,225