Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Additional Information (Detail)

v3.5.0.2
Fair Value Measurements - Additional Information (Detail) - USD ($)
6 Months Ended
Jul. 31, 2016
Jan. 31, 2016
Jul. 31, 2015
Fair Value Measurements Disclosure [Line Items]      
Fair value measurements of our financial assets and liabilities $ 12,976,000 $ 15,922,000  
Assets measured at fair value on nonrecurring basis $ 0   $ 0
Maximum maturity of marketable securities Three months or less    
Cash equivalents and marketable securities $ 50,900,000 71,100,000  
Restricted cash related to performance obligations 185,000 82,000  
Fair Value, Inputs, Level 3 [Member]      
Fair Value Measurements Disclosure [Line Items]      
Fair value measurements of our financial assets and liabilities 0 0  
Cash Related to Performance Obligations [Member]      
Fair Value Measurements Disclosure [Line Items]      
Restricted cash related to performance obligations $ 200,000 $ 100,000