Debt - Additional Information (Detail) - USD ($)				1 Months Ended	6 Months Ended
	May. 28, 2014	May. 23, 2014	May. 01, 2014	Jun. 30, 2012	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Jan. 31, 2013
Debt Instrument [Line Items]
Repayment of principal and accrued interest						$ 3,000,000
Warrant value recorded in equity							$ 108,122
Line of credit facility, loan origination cost						$ 82,685
Warrant [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount							108,122
Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Repayment of principal amount			$ 603,000
Silicon Valley Bank [Member] | Loan and security agreement [Member]
Debt Instrument [Line Items]
Loan and security agreement, maximum credit				$ 3,000,000
Loan and security agreement, amount drawn								$ 3,000,000
Loan and security agreement, interest rate				4.50%
Loan and security agreement, payback period				24 months
Repayment of principal and accrued interest		$ 2,400,000
Debt Instrument, Unamortized Discount		$ 38,000
Square 1 Bank [Member] | Maximum [Member]
Debt Instrument [Line Items]
Cash burn under credit facility					3.00
Square 1 Bank [Member] | Minimum [Member]
Debt Instrument [Line Items]
Cash burn under credit facility					1.00
Square 1 Bank [Member] | Loan and security agreement [Member]
Debt Instrument [Line Items]
Loan and security agreement, amount drawn							$ 4,500,000
Loan and security agreement, available credit	$ 4,500,000
Fixed interest rate							5.50%
Loan and security agreement, amount of other indebtedness	400,000
Warrants exercisable, stock issued							22,881
Warrant exercise price per share							$ 5.90
Warrant expiration date					Dec. 31, 2024
Line of credit facility, loan origination cost	$ 82,685
Loan and security agreement, Amortization period	42 months