Consolidated Statements of Stockholders' Equity (unaudited) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2016	$ 42,352	$ 27	$ 132,246	$ (89,618)	$ (303)
Balance, shares at Dec. 31, 2016		27,150,674
Stock-based compensation	4,872		4,872
Issuance of common stock in follow-on offering, net	9,870	$ 1	9,869
Issuance of common stock in follow-on offering, net, shares		553,825
Exercise of stock options	$ 2,087		2,087
Exercise of stock options, shares	370,084	370,084
Issuance of shares under employee stock purchase plan	$ 1,540		1,540
Issuance of shares under employee stock purchase plan, shares		128,786
Other comprehensive income	323				323
Net loss	(13,870)			(13,870)
Balance at Sep. 30, 2017	$ 47,174	$ 28	$ 150,614	$ (103,488)	$ 20
Balance, shares at Sep. 30, 2017		28,203,369