Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.10.0.1
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
12 Months Ended
Jan. 01, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Product Information [Line Items]        
Warrants exercise or expiration period   Sep. 30, 2018    
Cash and cash equivalents, maturity description   90 days or less    
Impairment losses   $ 0 $ 0 $ 0
Interest or penalties related to income taxes   $ 0 $ 0 $ 0
Subsequent Event [Member] | ASU 2018-11 [Member]        
Product Information [Line Items]        
ROU assets $ 200,000      
Lease liabilities 2,500,000      
Derecognition of the deferred rent $ 2,300,000      
Maximum [Member]        
Product Information [Line Items]        
Short-term contractual maturities   1 year    
Property and equipment, estimated useful lives   7 years    
Minimum [Member]        
Product Information [Line Items]        
Long-term contractual maturities   1 year    
Property and equipment, estimated useful lives   3 years