Income Taxes Foreign and U.S. Federal and State Tax Carryforwards for Income Tax Purposes (Details) $ in Thousands	12 Months Ended
	Jan. 31, 2017 USD ($)
Operating Loss and Tax Credit Carry Forward
Foreign net operating loss carryforwards	$ 19,472
Internal Revenue Service (IRS)
Operating Loss and Tax Credit Carry Forward
Research and experimentation credit carryforward	99,194
Net operating loss carryforward	13,863
Foreign tax credits	12,297
Alternative minimum tax credits	2,682
Miscellaneous	$ 1,939
Internal Revenue Service (IRS) | Minimum
Operating Loss and Tax Credit Carry Forward
Expiration date of operating loss carryforwards	Jan. 31, 2020
Internal Revenue Service (IRS) | Maximum
Operating Loss and Tax Credit Carry Forward
Expiration date of operating loss carryforwards	Jan. 31, 2037
State and Local Jurisdiction
Operating Loss and Tax Credit Carry Forward
Research and experimentation credit carryforward	$ 22,629
Net operating loss carryforward	175,233
Miscellaneous	$ 699
State and Local Jurisdiction | Minimum
Operating Loss and Tax Credit Carry Forward
Expiration date of operating loss carryforwards	Jan. 31, 2018
State and Local Jurisdiction | Maximum
Operating Loss and Tax Credit Carry Forward
Expiration date of operating loss carryforwards	Jan. 31, 2037
Research Tax Credit Carryforward | Internal Revenue Service (IRS) | Minimum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2019
Research Tax Credit Carryforward | Internal Revenue Service (IRS) | Maximum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2037
Research Tax Credit Carryforward | State and Local Jurisdiction | Minimum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2018
Research Tax Credit Carryforward | State and Local Jurisdiction | Maximum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2032
Foreign Tax Credits | Internal Revenue Service (IRS) | Minimum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2020
Foreign Tax Credits | Internal Revenue Service (IRS) | Maximum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2027
Childcare Tax Credit | Internal Revenue Service (IRS) | Minimum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2023
Childcare Tax Credit | Internal Revenue Service (IRS) | Maximum
Operating Loss and Tax Credit Carry Forward
Expiration date of tax credit carryforwards	Jan. 31, 2037