Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Contingencies And Commitments [Line Items]
Lease expense	$ 300,000	$ 300,000	$ 100,000
Lease term	89 months
CDC [Member]
Contingencies And Commitments [Line Items]
Royalties received	$ 20,000
Granted royalty on sales of the next BEMA product	1.00%
Net sales of next BEMA Product	$ 7,500,000
Minimum [Member] | CDC [Member]
Contingencies And Commitments [Line Items]
Royalties received	$ 375,000