Summary of Significant Accounting Policies - Voluntary Recall (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021
Inventory [Line Items]
Inventories	$ 9,989	$ 16,049
ENROUTE [Member]
Inventory [Line Items]
Inventories	2,227
Inventory Recall Expense	237
Contingent liabilities requiring accrual	1,696	15
ENROUTE, Held By Customer [Member]
Inventory [Line Items]
Inventories	1,696
Voluntary Recall
Inventory [Line Items]
Inventories	$ 4,160	$ 334