XML 114 R90.htm IDEA: XBRL DOCUMENT v3.8.0.1
Fair Value Measurements - Common Stock Warrants (Detail) - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Weighted-average exercise price $ 0.09  
Term (years) 4 years 8 months  
Fair value of common stock warrants $ 19.21 $ 14.49
Warrant    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Common stock warrants outstanding (in shares) 354,350 354,350