CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (40,448)	$ (53,689)
Other comprehensive loss:
Unrealized gain on available-for-sale investments, net		105
Total comprehensive loss	$ (40,448)	$ (53,584)