Summary of Significant Accounting Policies - Opening and Closing Balances of the Company's Contract Assets and Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Contract assets, current portion
Beginning balance	$ 496
Ending balance	0
Change	(496)
Contract assets
Beginning balance	3,216
Ending balance	3,997
Change	781
Deferred Revenue, Current
Beginning balance	14,991
Ending balance	14,870
Change	(121)
Deferred Revenue
Beginning balance	27,852
Ending balance	23,862
Change	(3,990)
Deferred revenue related to leases, current portion	1,700	$ 3,800
Deferred revenue related to leases, noncurrent portion	$ 2,700	$ 7,900