Business Combination - Schedule of Pro Forma Results of Operations (Detail) - Allenex [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue:
Testing revenue	$ 7,246	$ 7,044	$ 13,698	$ 14,140
Product revenue	4,027	4,024	7,887	8,062
Other revenue	100	163	288	356
Total revenue	11,373	11,231	21,873	22,558
Net loss	$ (8,809)	$ (5,097)	$ (15,123)	$ (8,504)
Weighted-average shares used to compute basic net loss per common share	11,835,405	11,835,405	11,824,993	11,824,993
Net loss per common share - basic and diluted	$ (0.74)	$ (0.43)	$ (1.28)	$ (0.72)