Accounts Receivable and Allowance for Credit Losses (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Accounts Receivable
Unbilled revenue	$ 17,900		$ 8,700
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Period	598	$ 837
Expense	112	341
Write off	(156)	(274)
Other	(1)	0
Balance at End of Period	$ 553	$ 904