Income Taxes - Income Tax (Benefit) Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 0	$ 0	$ 0
State	268	10	4
Foreign	1,134	767	197
Current income tax provision (benefit)	1,402	777	201
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	0	0	0
Deferred income tax provision (benefit)	0	0	0
Total	$ 1,402	$ 777	$ 201