Revenue - Schedule of Revenue Disaggregated by Type of Products and Services (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Total revenue	$ 85,071	$ 55,663	$ 38,448
Sequencing Revenue
Disaggregation Of Revenue [Line Items]
Total revenue	43,519	32,978	22,759
Development Support Revenue
Disaggregation Of Revenue [Line Items]
Total revenue	39,552	12,685	15,689
Development Revenue Regulatory Milestones
Disaggregation Of Revenue [Line Items]
Total revenue	2,000	10,000
Development Revenue
Disaggregation Of Revenue [Line Items]
Total revenue	$ 41,552	$ 22,685	$ 15,689