XML 75 R61.htm IDEA: XBRL DOCUMENT v3.3.1.900
Income Taxes - Additional Information (Details) - USD ($)
$ in Thousands
 12 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Jan. 31, 2014
Income Tax Disclosure [Line Items]      
Federal statutory income tax rate 34.00%    
Valuation allowance increase, amount $ (64,800) $ (52,200) $ (43,100)
Release of deferred tax valuation allowance 0 $ (1,117) $ (2,590)
Excess tax benefits from employee stock option exercises included in net operating loss and research and development tax credit forwards 18,300    
Federal      
Income Tax Disclosure [Line Items]      
Net operating loss carry forwards 423,700    
Tax credit carry forward $ 10,700    
Operating loss carryforwards expiration year 2025    
Research and development tax credit carryforwards expiration year 2025    
State      
Income Tax Disclosure [Line Items]      
Net operating loss carry forwards $ 392,300    
Tax credit carry forward 11,500    
Foreign      
Income Tax Disclosure [Line Items]      
Net operating loss carry forwards $ 125,600