Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit	Total
Balance, Beginning at Dec. 31, 2018		$ 253,222	$ (233)	$ (140,474)	$ 112,515
Balance, Beginning (in shares) at Dec. 31, 2018	23,187,219
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon under equity incentive and employee stock purchase plans		390			390
Issuance of common stock upon under equity incentive and employee stock purchase plans (in shares)	205,315
Stock-based compensation expense		1,979			1,979
Other comprehensive gain			44		44
Net loss				(14,103)	(14,103)
Balance, Ending at Mar. 31, 2019		255,591	(189)	(154,577)	100,825
Balance, Ending (in shares) at Mar. 31, 2019	23,392,534
Balance, Beginning at Dec. 31, 2019		297,846	(221)	(217,661)	$ 79,964
Balance, Beginning (in shares) at Dec. 31, 2019	27,217,649				27,217,649
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon under equity incentive and employee stock purchase plans		406			$ 406
Issuance of common stock upon under equity incentive and employee stock purchase plans (in shares)	217,056
Stock-based compensation expense		2,048			2,048
Other comprehensive gain			328		328
Net loss				(20,080)	(20,080)
Balance, Ending at Mar. 31, 2020		$ 300,300	$ 107	$ (237,741)	$ 62,666
Balance, Ending (in shares) at Mar. 31, 2020	27,434,705				27,434,705