Collaboration and Commercial Technology Licensing Agreements (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Collaboration and specimen transfer agreements
Collaboration agreements
Collaboration expense	$ 573,000	$ 935,000
Technology license agreements | Cost of product revenues
Collaboration agreements
Costs recorded under collaborative arrangements	$ 69,000	$ 95,000