Quarterly report pursuant to Section 13 or 15(d)

Organization and Description of Business - Additional Information (Detail)

v3.7.0.1
Organization and Description of Business - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
Sep. 09, 2016
Mar. 31, 2017
Dec. 31, 2016
Apr. 27, 2016
Organization And Nature Of Business [Line Items]        
Common Stock Par Or Stated Value Per Share   $ 0.001 $ 0.001  
National Holdings Corporation [Member]        
Organization And Nature Of Business [Line Items]        
Merger Agreement Minimum Percentage Of Shares In Tender Offer To Completed Merger 56.60%      
Merger Agreement Termination Fee $ 22.9      
Common Stock Par Or Stated Value Per Share $ 0.02     $ 0.02
Business Acquisition, Share Price $ 3.25     $ 3.25