Consolidated Statements of Stockholders’ Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Beginning balance, common stock (in shares) at Dec. 31, 2017		32,249
Beginning balance at Dec. 31, 2017	$ 167,109	$ 32	$ 257,101	$ (409)	$ (89,615)
Exercise of common stock options (in shares)	683
Exercise of stock options	$ 1,546	$ 1	1,545
Vesting of restricted stock awards (in shares)		9
Vesting of restricted stock awards and restricted stock units	28		28
Stock-based compensation expense	9,407		9,407
Other comprehensive income	331			331
Net income (loss)	$ (27,379)				(27,379)
Ending balance, common stock (in shares) at Dec. 31, 2018	32,941	32,941
Ending balance at Dec. 31, 2018	$ 104,129	$ 33	268,081	(78)	(163,907)
Issuance of common stock from at the market offering, net of issuance costs (in shares)		448
Issuance of common stock from at the market offering, net of issuance costs	$ 3,511	$ 1	3,510
Exercise of common stock options (in shares)	185	185
Exercise of stock options	$ 437		437
Vesting of restricted stock awards (in shares)		164
Vesting of restricted stock awards and restricted stock units	27		27
Stock-based compensation expense	9,609		9,609
Other comprehensive income	132			132
Net income (loss)	$ 56,823				56,823
Ending balance, common stock (in shares) at Dec. 31, 2019	33,738	33,738
Ending balance at Dec. 31, 2019	$ 174,593	$ 34	$ 281,664	$ 54	$ (107,159)