Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Commitments And Contingencies [Line Items]
Operating leases, rent expense	$ 53,000	$ 66,000
Reagents and Equipment
Commitments And Contingencies [Line Items]
Purchase obligations	$ 3,200,000
Minimum | Non Cancelable Operating Lease
Commitments And Contingencies [Line Items]
Operating leases, renewal term	2 years
Maximum | Non Cancelable Operating Lease
Commitments And Contingencies [Line Items]
Operating leases, renewal term	3 years