Balance Sheet Components - Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Balance Sheet Components
Reserves for refunds to insurance carriers	$ 17,326	$ 17,210	$ 20,304	$ 17,366
Accrued charges for third-party testing	5,445	5,849
Testing and laboratory materials from suppliers	5,561	3,799
Marketing and corporate affairs	7,563	7,853
Legal, audit and consulting fees	18,645	11,758
Accrued shipping charges	4,792	969
Sales tax payable	788	2,230
Accrued third-party service fees	14,483	13,442
Clinical trials and studies	17,835	11,218
Operating lease liabilities, current portion	5,239	5,752
Fixed asset purchases	5,370	1,853
Other accrued interest	2,695	1,078
Other accrued expenses	10,895	10,342
Total other accrued liabilities	$ 116,637	$ 93,353