Business Combinations and Asset Acquisitions - Summary of Fair Values of Assets Acquired and Liabilities Assumed as of Acquisition Date (Detail) - USD ($) $ in Thousands		12 Months Ended
	May 04, 2018	Dec. 31, 2018
Customer Relationships [Member] | TruSight [Member]
Business Acquisition [Line Items]
Estimated useful life of identified intangible asset		2 years
Customer Relationships [Member] | TruSight [Member] | HLA [Member]
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	$ 380
Estimated useful life of identified intangible asset	2 years 7 months 6 days
Illumina [Member]
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	$ 5,202
Illumina [Member] | Acquired in-process technology AlloSeq [Member] | HLA [Member]
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	2,719
Illumina [Member] | Acquired in-process technology AlloSeq [Member] | BMT [Member]
Business Acquisition [Line Items]
Estimated fair value of identified intangible assets	$ 2,103