Acquisitions - Summary of Fair Value of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 10, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 211,083	$ 198,601	$ 197,892
Human Longevity, Inc.
Business Acquisition [Line Items]
Inventory	$ 534	534
Measurement period adjustments, inventory		0
Prepaid assets	185	185
Measurement period adjustments, prepaid assets		0
Property and equipment	16,839	16,839
Measurement period adjustments, property and equipment		0
Long-term assets	346	346
Measurement period adjustments, long term assets		0
Goodwill	12,232	12,482
Measurement period adjustments, goodwill		250
Total assets acquired	37,346	37,346
Measurement period adjustments, total assets acquired		0
Long-term liabilities	(346)	(346)
Measurement period adjustments, long term liabilities		0
Net assets acquired	37,000	37,000
Measurement period adjustments, net assets acquired		0
Human Longevity, Inc. | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets	$ 4,100	3,830
Measurement period adjustments, identifiable intangible assets		(270)
Customer relationship, useful life (in years)	7 years
Human Longevity, Inc. | Internally Developed Software
Business Acquisition [Line Items]
Identifiable intangible assets	$ 3,110	3,130
Measurement period adjustments, identifiable intangible assets		$ 20