Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Additional Information (Detail)

v3.2.0.727
Fair Value Measurements - Additional Information (Detail) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2015
Dec. 31, 2014
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]    
Warrant liability $ 2,967 $ 3,002
Maximum maturity period of cash and cash equivalents 90 days  
Maximum maturity period of short-term investments 1 year  
Series A and Series B Warrants issued in July 2014 Financing [Member]    
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]    
Warrants outstanding and exercisable 0  
Maximum [Member]    
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]    
Maturity period of securities 1 year