Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Fair Value of Financial Assets Measured on Recurring Basis (Detail)

v3.20.1
Fair Value Measurements - Fair Value of Financial Assets Measured on Recurring Basis (Detail) - USD ($)
$ in Thousands
Jan. 31, 2020
Jan. 31, 2019
Marketable securities:    
Marketable securities $ 4,617 $ 10,359
U.S. Treasury Notes and Bonds [Member]    
Marketable securities:    
Marketable securities 3,360 7,072
U.S. Agency Bonds [Member]    
Marketable securities:    
Marketable securities   992
Corporate Bonds [Member]    
Marketable securities:    
Marketable securities 1,257 2,295
Fair Value, Measurements, Recurring [Member]    
Assets:    
Cash equivalents 1,408 2,887
Marketable securities:    
Total 6,025 13,246
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Notes and Bonds [Member]    
Marketable securities:    
Marketable securities 3,360 7,072
Fair Value, Measurements, Recurring [Member] | U.S. Agency Bonds [Member]    
Marketable securities:    
Marketable securities   992
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]    
Marketable securities:    
Marketable securities 1,257 2,295
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets:    
Cash equivalents 1,408 2,724
Marketable securities:    
Total 4,768 9,796
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Treasury Notes and Bonds [Member]    
Marketable securities:    
Marketable securities 3,360 7,072
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets:    
Cash equivalents   163
Marketable securities:    
Total 1,257 3,450
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Agency Bonds [Member]    
Marketable securities:    
Marketable securities   992
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]    
Marketable securities:    
Marketable securities $ 1,257 $ 2,295