Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Income Taxes [Line Items]
Benefits related to stock options	$ 707,000
Deferred tax asset valuation allowance percentage in each of the last two years	100.00%
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Net operating loss carryforwards	69,888,000
Operating loss carryforwards, expiration year	2032
Research and development credits	284,000
Research and development credits, expiration year	2032
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carryforwards	29,881,000
Operating loss carryforwards, expiration year	2032
Research and development credits	$ 176,000
Research and development credits, expiration year	2032