Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance (in shares) at Dec. 31, 2017		50,239,000
Beginning Balance at Dec. 31, 2017	$ 164,611	$ 0	$ 418,354	$ 41	$ (253,784)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		50,000
Exercise of common stock options	45		45
Restricted stock awards, net (in shares)		(156,000)
Restricted stock awards, net	0
Issuance of common stock related to employee stock purchase plan (in shares)		174,000
Issuance of common stock related to employee stock purchase plan	314		314
Issuance of common stock related to RSU vesting (in shares)		1,367,000
Issuance of common stock related to RSU vesting	1	$ 1
Shares withheld related to net share settlement (in shares)		(515,000)
Shares withheld related to net share settlement	(1,638)		(1,638)
Stock-based compensation	16,802		16,802
Other comprehensive income (loss)	(300)			(300)
Net loss	$ (61,822)				(61,822)
Ending Balance (in shares) at Dec. 31, 2018	51,159,000	51,159,000
Ending Balance at Dec. 31, 2018	$ 118,013	$ 1	433,877	(259)	(315,606)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		285,000
Exercise of common stock options	588		588
Restricted stock awards, net (in shares)		(182,000)
Restricted stock awards, net	0
Issuance of common stock related to employee stock purchase plan (in shares)		227,000
Issuance of common stock related to employee stock purchase plan	1,054		1,054
Issuance of common stock related to RSU vesting (in shares)		2,858,000
Issuance of common stock related to RSU vesting	0
Shares withheld related to net share settlement (in shares)		(459,000)
Shares withheld related to net share settlement	(1,847)		(1,847)
Stock-based compensation	19,392		19,392
Other comprehensive income (loss)	214			214
Net loss	$ (25,478)				(25,478)
Ending Balance (in shares) at Dec. 31, 2019	53,888,000	53,888,000
Ending Balance at Dec. 31, 2019	$ 111,936	$ 1	$ 453,064	$ (45)	$ (341,084)