Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Deferred tax assets:
Net operating loss carryforwards	$ 14,238	$ 12,658
Accrued liabilities	5,682	5,429
Tax credit carryforwards	5,695	1,984
Intangible assets		163
Deferred Revenue	5,270
Valuation allowance	(29,154)	(19,383)	(16,700)
Total deferred tax assets	1,731	851
Deferred tax liabilities:
Depreciation and amortization	(1,450)	(851)
Total deferred tax liabilities	(1,450)	(851)
Net deferred taxes	281
Recorded as:
Current deferred tax assets	2,886	2,750
Current valuation allowance	(2,572)	(2,750)
Non-current deferred tax assets	26,548	16,633
Non-current valuation allowance	(26,581)	(16,633)
Net deferred taxes	$ 281