Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Summary of Marketable Securities by Security Type (Detail)

v3.19.3
Fair Value Measurements - Summary of Marketable Securities by Security Type (Detail) - USD ($)
$ in Thousands
Oct. 31, 2019
Jan. 31, 2019
Schedule of Available-for-Sale Securities [Line Items]    
Amortized Cost $ 7,767 $ 10,364
Gross Unrealized Gains 101 17
Gross Unrealized Losses   (22)
Fair Value 7,868 10,359
U.S. Treasury Notes and Bonds [Member]    
Schedule of Available-for-Sale Securities [Line Items]    
Amortized Cost 6,512 7,055
Gross Unrealized Gains 98 17
Fair Value 6,610 7,072
U.S. Agency Bonds [Member]    
Schedule of Available-for-Sale Securities [Line Items]    
Amortized Cost   1,001
Gross Unrealized Losses   (9)
Fair Value   992
Corporate Bonds [Member]    
Schedule of Available-for-Sale Securities [Line Items]    
Amortized Cost 1,255 2,308
Gross Unrealized Gains 3  
Gross Unrealized Losses   (13)
Fair Value $ 1,258 $ 2,295