Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plan - Additional Information (Detail)

v3.19.1
Employee Benefit Plan - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Molecular Templates 401(k) Plan    
Defined Contribution Plan Disclosure [Line Items]    
Employer discretionary contribution amount $ 146,000 $ 0