Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Income Tax [Line Items]
Deferred tax assets, increase in valuation allowance	$ 68,000,000	$ 66,600,000	$ 28,800,000
Gross unrecognized tax benefit	15,470,000	$ 13,874,000	$ 4,676,000	$ 479,000
Current or cumulative interest and penalties related to uncertain tax positions	0
Federal
Income Tax [Line Items]
Net operating loss carryforwards	392,400,000
Net operating loss carryforwards, excess tax benefits from stock-based compensation	27,700,000
Research and development tax credit carryforwards	$ 10,000,000
Expiration of federal tax credit carryforwards, beginning	2028
State
Income Tax [Line Items]
Net operating loss carryforwards	$ 402,200,000
Net operating loss carryforwards, excess tax benefits from stock-based compensation	30,200,000
Research and development tax credit carryforwards	$ 9,900,000
Tax credit carryforwards expiration, description	state research and development tax credit carryforwards have no expiration date.
Federal And State Jurisdiction
Income Tax [Line Items]
Expiration of federal and state net operating loss carryforwards, beginning	2028
Non-U.S.
Income Tax [Line Items]
Undistributed earnings of foreign subsidiaries	$ 7,300,000