CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Stock-based compensation expense	$ 14,332	$ 4,685	$ 36,124	$ 11,223
Cost of revenues
Stock-based compensation expense	1,165	322	2,735	697
Research and development
Stock-based compensation expense	4,405	1,560	10,995	3,722
Sales and marketing
Stock-based compensation expense	5,947	2,093	15,425	4,456
General and administrative
Stock-based compensation expense	$ 2,815	$ 710	$ 6,969	$ 2,348