Summary of Significant Accounting Policies and Other Items - Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Depreciation expense
Selling, general and administrative expenses	$ 457	$ 876	$ 683
Total depreciation and amortization	36,308	40,520	38,854
Product revenue
Depreciation expense
Cost of sales	3,176	3,506	3,304
Rental revenue
Depreciation expense
Cost of sales	25,812	28,063	24,881
Field service and other revenue
Depreciation expense
Cost of sales	$ 6,863	$ 8,075	$ 9,986