Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
Deferred tax asset valuation allowance	$ 26,842,000	$ 27,673,000
Tax credit carryforwards	2,700,000
Tax credit carryforwards expiration period	2018
Period of increase in ownership percentage	3 years
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	59,700,000
Domestic Tax Authority [Member] | Expire in 2022 and 2023 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	41,800,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	3,400,000
Expired state net operating losses	300,000
Federal and state net operating loss carryforwards	$ 3,400,000
Operating loss carryforwards expiration period	2015
Minimum [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards expiration period	2022
Maximum [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards expiration period	2023