Quarterly report pursuant to Section 13 or 15(d)

Merger with Private Molecular - Purchase Price for Threshold on Closing Date of Merger (Parenthetical) (Detail)

v3.8.0.1
Merger with Private Molecular - Purchase Price for Threshold on Closing Date of Merger (Parenthetical) (Detail)
 9 Months Ended
Aug. 01, 2017
$ / shares
shares
Sep. 30, 2017
$ / shares
Dec. 31, 2016
$ / shares
Business Acquisition [Line Items]      
Reverse stock split of common stock, description   11-for-1 reverse stock split  
Reverse stock split of common stock conversion ratio 11    
Common stock closing price   $ 6.97 $ 3.07
Threshold      
Business Acquisition [Line Items]      
Number of share of the combined company owned by Threshold stockholders | shares 6,508,356    
Reverse stock split of common stock, description   11-for-1 reverse stock split  
Reverse stock split of common stock conversion ratio 11    
Price per share of Threshold common stock $ 5.94    
Common stock closing price $ 0.54