Commitments and Contingencies - Additional Information (Detail) - Menlo Park, California [Member] $ in Millions	1 Months Ended		9 Months Ended
	May. 31, 2015 ft²	Mar. 31, 2014 ft²	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Operating facility lease area	15,000	12,943
Operating facility lease term	24 months	39 months
Total obligation under lease | $			$ 1.6	$ 1.5
Lease commencement date			Mar. 01, 2016