Quarterly report pursuant to Section 13 or 15(d)

Note Warrants - Additional Information (Detail)

v3.7.0.1
Note Warrants - Additional Information (Detail) - $ / shares
6 Months Ended
Jun. 30, 2017
Dec. 31, 2016
Aug. 01, 2014
Class of Warrant or Right [Line Items]      
Number of warrants or rights outstanding 20,272,873 27,214,775  
Note Warrants [Member]      
Class of Warrant or Right [Line Items]      
Number of warrants or rights outstanding 3,315,878 3,315,878 3,321,416
Warrant exercise price per share     $ 3.00
Note Warrants [Member] | Minimum [Member]      
Class of Warrant or Right [Line Items]      
Warrants expiration date 2018-06    
Note Warrants [Member] | Maximum [Member]      
Class of Warrant or Right [Line Items]      
Warrants expiration date 2019-06