Acquisitions - Additional Information (Detail) - Genoptix - USD ($) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 10, 2018	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Cash consideration paid	$ 127,000
Payment for working capital adjustment	$ 2,000		$ 2,400	$ 2,400
Common stock issued (in shares)	1,000,000
Payment for working capital adjustment, cash portion		$ 400		400
Identifiable intangible assets	$ 71,792			$ 68,329
Acquired receivable	16,600
Fair value adjustment	1,500
Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets	$ 54,200
Intangible assets, useful life	15 years
Trade Names
Business Acquisition [Line Items]
Identifiable intangible assets	$ 700
Intangible assets, useful life	1 year
Common Stock
Business Acquisition [Line Items]
Common stock issued (in shares)	1,000,000.0
Trademarks
Business Acquisition [Line Items]
Identifiable intangible assets	$ 13,400