Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) clinical_trial	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Operating Leased Assets [Line Items]
Total rent expense under operating leases	$ 862,000	$ 835,000	$ 659,000
Current deferred rent	140,000	126,000
Other long-term liabilities	101,000	241,000
Purchase obligations	621,000
Annual purchases, raw materials	1,200,000	1,200,000	724,000
Annual purchases	$ 97,000	$ 105,000	$ 131,000
Number of clinical trials | clinical_trial	3
Materials [Member]
Operating Leased Assets [Line Items]
Purchase obligations	$ 225,000
Upgrade To Manufacturing Facility [Member]
Operating Leased Assets [Line Items]
Purchase obligations	114,000
Raw Materials [Member]
Operating Leased Assets [Line Items]
Purchase obligations	$ 282,000