Consolidated Statements of Comprehensive Loss Parentheticals - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Consolidated Statements of Operations [Abstract]
Stock-based compensation expense associated with research and development expense	$ 1,029	$ 1,698	$ 5,154	$ 5,369
Stock-based compensation expense associated with selling, general and administrative expense	$ 875	$ 1,864	$ 5,440	$ 5,370