Related Party Transactions - Additional Information (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Research and development expense	$ 157,610,000	$ 82,887,000	$ 39,514,000
Brightstar \| CHC, Inc. \| Loan and Security Agreement
Related Party Transaction [Line Items]
Ownership percentage	31.00%
Clinical Reference Laboratory, Inc.
Related Party Transaction [Line Items]
Laboratory services	$ 100,000
Clinical Reference Laboratory, Inc. \| Loan and Security Agreement
Related Party Transaction [Line Items]
Principal amount owed under loan agreement	0	1,300,000
Clinical Reference Laboratory, Inc. \| Service Agreement
Related Party Transaction [Line Items]
Research and development expense	700,000	900,000	400,000
Payments for research and development expense	700,000	800,000	400,000
Laboratory services		200,000
Employees contributions under 401(K) plan	0	0	$ 600,000
Clinical Reference Laboratory, Inc. \| CHC, Inc. \| Loan and Security Agreement
Related Party Transaction [Line Items]
Ownership percentage			100.00%
Aggregate borrowings	$ 2,800,000
Fixed interest rate	6.00%
Debt instrument term	15 years
Interest expense on borrowings	$ 100,000	100,000	$ 100,000
Debt instrument principal and interest payment	$ 1,400,000
Principal amount owed under loan agreement		$ 300,000	$ 300,000
Clinical Reference Laboratory, Inc. \| Brightstar \| Minimum
Related Party Transaction [Line Items]
Percentage of common stock holding	5.00%

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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