CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (9,255)	$ (5,869)	$ (18,394)	$ (11,554)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment	(4)	(15)	(9)
Change in unrealized gain on available-for-sale debt securities	37		121
Comprehensive loss	$ (9,222)	$ (5,884)	$ (18,282)	$ (11,554)