Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	3 Months Ended								12 Months Ended
	Mar. 31, 2014 USD ($) ft²	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) ft² Building	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jul. 31, 2011 USD ($) ft²	Mar. 31, 2008 ft²	Mar. 31, 2007 ft²	Mar. 31, 2001 ft²
Commitments and Contingencies [Line Items]
Lease agreement, term	8 years 1 month												11 years	2 years	5 years	10 years
Lease agreement, space | ft²										45,000			55,694	7,350	2,500	25,000
Lease agreement, expiration date													May 31, 2023
Lease agreement, letter of credit issued													$ 200,000
Lease agreement, commencement date	Aug. 01, 2014
Future minimum rental commitment, 2016		$ 2,343,000								$ 2,343,000
Future minimum rental commitment, 2017		1,888,000								1,888,000
Future minimum rental commitment, 2018		1,434,000								1,434,000
Future minimum rental commitment, 2019		1,418,000								1,418,000
Future minimum rental commitment, 2020		1,371,000								$ 1,371,000
Lease termination description										The Company terminated the lease on the 7,350 square feet of space in the first quarter of 2015.
Lease agreement, number buildings leased | Building										4
Operating leases, rent expense										$ 2,619,000	$ 2,735,000	$ 2,437,000
Operating leases, deferred rent liabilities		1,899,000				$ 1,956,000				1,899,000	1,956,000	2,028,000
Research and development expenses		1,431,000	$ 1,490,000	$ 1,252,000	$ 1,568,000	$ 1,328,000	$ 1,650,000	$ 1,430,000	$ 1,201,000	5,740,000	5,609,000	7,341,000
Purchase orders, supply agreements and other contractual obligations		5,729,000								5,729,000
Licensing Agreements
Commitments and Contingencies [Line Items]
Research and development expenses										$ 7,000	$ 7,000	$ 302,000
Lease for three buildings
Commitments and Contingencies [Line Items]
Lease agreement, space | ft²										41,000
Lease agreement, expiration date										Jun. 30, 2017
Lease for the fourth building
Commitments and Contingencies [Line Items]
Lease agreement, space | ft²										4,000
Lease agreement, expiration date										Sep. 30, 2019
Before Amendment
Commitments and Contingencies [Line Items]
Lease agreement, space | ft²	55,694
Security deposit	$ 200,000								200,000
After Amendment
Commitments and Contingencies [Line Items]
Lease agreement, space | ft²	75,594
Security deposit	$ 450,000								$ 450,000
Future minimum rental commitment, 2016		1,371,000								$ 1,371,000
Future minimum rental commitment, 2017		1,371,000								1,371,000
Future minimum rental commitment, 2018		1,371,000								1,371,000
Future minimum rental commitment, 2019		1,371,000								1,371,000
Future minimum rental commitment, 2020		$ 1,371,000								$ 1,371,000
Expansion Space
Commitments and Contingencies [Line Items]
Lease agreement, space | ft²	19,900
Annual rent expense	$ 361,000