Commitment and Contingencies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitment to acquire equipment and services	$ 6,700		$ 6,700
Reimbursement received from government agency	1,400		5,300
Unfunded commitment	1,400		1,400
Equipment purchased under commitment	616		4,100
Remaining accounts payable to vendors	798		798
Rent expense	228	$ 233	655	$ 672
Rental income from noncancelable sublease	45	$ 45	136	$ 136
Future minimum rental payments to be received under sublease	$ 78		$ 78