Annual report pursuant to Section 13 and 15(d)

Organization and Description of Business - Additional Information (Detail)

v3.8.0.1
Organization and Description of Business - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
Sep. 09, 2016
Dec. 31, 2017
Dec. 01, 2017
Jun. 01, 2017
Dec. 31, 2016
Apr. 27, 2016
Organization And Nature Of Business [Line Items]            
Common Stock Par Or Stated Value Per Share   $ 0.001 $ 3.26 $ 1.90 $ 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% 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