Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Research and development credit carryforward	$ 4,799,000	$ 4,425,000
Pre-tax book loss for domestic operations	(11,085,000)	(9,409,000)	(5,909,000)
Pre-tax book loss for international operations	(5,093,000)	(2,035,000)	(1,575,000)
Unrecognized deferred tax assets	3,873,000
Unrecognized tax benefits	0	0	0
Unrecognized tax benefits, increase resulting from prior period tax positions	1,982,000	1,982,000
Unrecognized tax benefits, accrued interest and penalties	0
Federal [Member]
Income Tax Contingency [Line Items]
Operating loss carryforward	129,976,000
Operating loss Carryforward expiration date	Begin to expire in 2019
Research and development credit carryforward	4,697,000
Federal research and development credit credit carry forward expiry	2022
State [Member]
Income Tax Contingency [Line Items]
Operating loss carryforward	71,470,000
Foreign [Member]
Income Tax Contingency [Line Items]
Operating loss carryforward	$ 14,098,000
Operating loss Carryforward expiration date	Begin to expire in 2016
Minimum [Member] | State [Member]
Income Tax Contingency [Line Items]
State Operating loss carryforward expiry date	5 years
Maximum [Member] | State [Member]
Income Tax Contingency [Line Items]
State Operating loss carryforward expiry date	20 years