Collaboration and Commercial Technology Licensing Agreements (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Collaboration and specimen transfer agreements
Collaboration agreements
Collaboration expense	$ 3,200,000	$ 912,000	$ 3,800,000	$ 1,800,000
Technology license agreements | Cost of product revenues
Collaboration agreements
Costs recorded under collaborative arrangements	$ 66,000	$ 94,000	$ 135,000	$ 190,000