Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended				6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Federal	Dec. 31, 2013 Federal	Jun. 30, 2014 State and Local Jurisdiction	Dec. 31, 2013 State and Local Jurisdiction	Dec. 31, 2013 Research and Development Federal	Dec. 31, 2013 Research and Development State and Local Jurisdiction
Summary Of Net Deferred Tax Assets [Line Items]
Provision for income taxes	$ 640,000	$ 85,000	$ 640,000	$ 85,000
Net federal operating loss						43,900,000		40,700,000
Net operating losses carry forwards, expiration year					2027		2016
Research and development tax credit carry forward									600,000	500,000
Valuation allowance expiry year					2016
Percentage of ownership change, limitations on utilization of net operating loss (NOL) and research and development (R&D) credit carry forwards					50.00%
Ownership change test period, limitations on utilization of net operating loss (NOL) and research and development (R&D) credit carry forwards					3 years
Accrued interest or penalties associated with unrecognized tax benefits	$ 0		$ 0