The Company, Business Activities and Basis of Presentation - Composition of Net Revenues Recognized Disaggregated by Nature (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
The Company Business Activities And Basis Of Presentation [Line Items]
Total net revenues	$ 19,945	$ 17,756
Commercial Revenues [Member] | Commercial Revenues
The Company Business Activities And Basis Of Presentation [Line Items]
Total net revenues	19,907	17,655
Development Services Revenues [Member]
The Company Business Activities And Basis Of Presentation [Line Items]
Total net revenues	$ 38	39
Kits and Specimen Collection Tubes (SCTs)
The Company Business Activities And Basis Of Presentation [Line Items]
Total net revenues		$ 62