Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Apr. 30, 2014	Apr. 30, 2013
Income Statement [Abstract]
Revenue	$ 40,921	$ 33,941
Cost of revenue	15,325	12,248
Gross profit	25,596	21,693
Operating expenses:
Research and development	12,914	11,317
Selling, general and administrative	6,755	5,157
Total operating expenses	19,669	16,474
Income from operations	5,927	5,219
Other income (loss), net	49	(5)
Income before income taxes	5,976	5,214
Provision for income taxes	716	473
Net income	$ 5,260	$ 4,741
Net income per share attributable to ordinary shareholders:
Basic	$ 0.18	$ 0.17
Diluted	$ 0.17	$ 0.16
Weighted-average shares used to compute net income per share attributable to ordinary shareholders:
Basic	28,976,339	27,056,932
Diluted	31,763,993	29,066,062