Accounts Receivable - Allowance (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 518	$ 429	$ 506	$ 353
Provisions (recoveries) for expected credit losses, net of adjustments	(12)	117	0	193
Accounts receivable written off, net of recoveries	(29)	0	(29)	0
Balance, end of period	$ 477	$ 546	$ 477	$ 546