Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments - Additional Information (Detail)

v3.8.0.1
Financial Instruments - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Mar. 31, 2017
Convertible Notes Payable [Member] | Acacia [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Number of warrants issued 3  
Warrants maturity period 4 years  
Primary Warrant [Member] | Acacia [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Warrants maturity period 5 years  
Amended Primary and Acacia Note Warrants [Member] | Initial Public Offering [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Warrant exercise price   $ 13.6088
Minimum [Member] | Acacia Note Warrants [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Fair market value of warrants   $ 334,000
Maximum [Member] | Acacia Note Warrants [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Fair market value of warrants   841,000
Bridge Loan [Member] | Acacia [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Line of credit maximum borrowing capacity   $ 8,000,000