Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.7.0.1
Stockholders' Equity - Additional Information (Detail)
$ / shares in Units, $ in Millions
 1 Months Ended 12 Months Ended
Jul. 24, 2015
$ / shares
shares
Jun. 30, 2016
USD ($)
$ / shares
shares
Jul. 31, 2015
USD ($)
$ / shares
shares
Dec. 31, 2016
$ / shares
shares
Dec. 31, 2015
$ / shares
shares
Schedule Of Stockholders Equity [Line Items]          
Common stock, shares authorized       300,000,000 300,000,000
Common stock, par value | $ / shares       $ 0.001 $ 0.001
Common stock, shares issued       43,058,827 39,833,023
Common stock, outstanding       43,058,827 39,833,023
Preferred Stock, shares issued       4,963 0
Preferred Stock, shares outstanding       4,963 0
Preferred Stock, shares authorized       4,963 4,963
Preferred Stock, par value | $ / shares       $ 0.001 $ 0.001
Gross proceeds from issuance initial public offering | $     $ 28.3    
Net proceeds from issuance initial public offering | $     $ 25.8    
Number of shares in a unit   1      
Warrant exercisable period   5 years      
Securities Purchase Agreement [Member]          
Schedule Of Stockholders Equity [Line Items]          
Per unit price of private placement | $ / shares   $ 2.015      
Number of units in the transaction   8,188,804      
Gross proceeds from private placement | $   $ 16.5      
Net proceeds from private placement | $   $ 15.3      
2016 PIPE [Member]          
Schedule Of Stockholders Equity [Line Items]          
Common stock, shares issued   3,225,804      
IPO [Member]          
Schedule Of Stockholders Equity [Line Items]          
Common stock, shares issued     9,090,909    
Per unit price of private placement | $ / shares     $ 2.75    
Over-Allotment Option [Member]          
Schedule Of Stockholders Equity [Line Items]          
Per unit price of private placement | $ / shares $ 2.75        
Number of shares, Options exercised 1,211,827        
Private Placement [Member] | 2016 PIPE [Member]          
Schedule Of Stockholders Equity [Line Items]          
Common stock, shares issued       43,058,827  
Common stock, outstanding       43,058,827  
Preferred Stock [Member]          
Schedule Of Stockholders Equity [Line Items]          
Number of preferred stock convertible into common stock shares       4,963  
Convertible preferred stock, shares issued upon conversion       1,000  
Percentage of beneficial ownership       9.99%  
Percentage of voting or approval rights       The preferred shares do not have any voting rights.  
Convertible preferred stock conversion basis       Each of the 4,963 shares of preferred stock are convertible into one share of the Company's common stock.  
Convertible Series A Preferred Shares [Member]          
Schedule Of Stockholders Equity [Line Items]          
Convertible preferred stock, shares issued upon conversion   1,000      
Number of shares in a unit   1      
Shares issued price per share | $ / shares   $ 2.015      
Convertible Series A Preferred Shares [Member] | 2016 PIPE [Member]          
Schedule Of Stockholders Equity [Line Items]          
Preferred Stock, shares issued   4,963      
Convertible Series A Preferred Shares [Member] | Private Placement [Member] | 2016 PIPE [Member]          
Schedule Of Stockholders Equity [Line Items]          
Preferred Stock, shares issued       4,963  
Preferred Stock, shares outstanding       4,963  
Tranche A Warrant [Member]          
Schedule Of Stockholders Equity [Line Items]          
Number of warrants   1      
Number of shares to be purchased by a warrant   0.4      
Exercise price | $ / shares   $ 2.00      
Tranche B Warrant [Member]          
Schedule Of Stockholders Equity [Line Items]          
Number of warrants   1      
Number of shares to be purchased by a warrant   0.2      
Exercise price | $ / shares   $ 3.00