FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)
3 Months Ended
Apr. 30, 2018
Fair Value Disclosures [Abstract]  
Fair Value Measurements, Recurring and Nonrecurring
Fair Value of Senior Convertible Notes
The following table provides details on the senior convertible notes as of April 30, 2018 and January 31, 2018. The difference between the face value and the carrying value of these notes is the result of the allocation between the debt and equity components, and unamortized debt issuance costs. Fair value of the senior convertible notes was estimated based on Level 2 fair value inputs.
 
April 30, 2018
 
January 31, 2018
 
Estimated Fair Value
 
Carrying Value
 
Face Value
 
Estimated Fair Value
 
Carrying Value
 
Face Value
 
(in thousands)
 
(in thousands)
Senior convertible notes
$
65,000

 
$
63,351

 
$
65,644

 
$
65,000

 
$
62,819

 
$
65,644