Consolidated Statements of Comprehensive Loss Parentheticals - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Consolidated Statements of Operations [Abstract]
Stock-based compensation expense associated with research and development expense	$ 1,138	$ 1,029	$ 3,608	$ 5,154
Stock-based compensation expense associated with selling, general and administrative expense	$ 1,574	$ 875	$ 4,741	$ 5,440