Short-Term Investments (Tables)

3 Months Ended

Apr. 30, 2014

Investments Debt And Equity Securities [Abstract]

Schedule of Short-Term Investments

At April 30, 2014, short-term investments consisted of the following (in thousands):

			Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Available-for-sale securities:
Asset-backed securities	$	3,700	$	3	$	—		$	3,703
Commercial paper		4,997		—		—			4,997
Corporate notes and bonds		23,845		25		—			23,870
U.S. agency obligations		102,595		32		(11	)		102,616
U.S. treasury securities		21,411		11		—			21,422
Total available-for-sale securities	$	156,548	$	71	$	(11	)	$	156,608

At January 31, 2014, short-term investments consisted of the following (in thousands):

			Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Available-for-sale securities:
Corporate notes and bonds	$	10,499	$	9	$	(1	)	$	10,507
U.S. agency obligations		15,111		7		—			15,118
Total available-for-sale securities	$	25,610	$	16	$	(1	)	$	25,625

Summary of Estimated Fair Value of Short-Term Investments, Designated as Available-for-Sale and Classified by Contractual Maturity

The following table summarizes the estimated fair value of our short-term investments, designated as available-for-sale and classified by the contractual maturity date of the securities as of the dates shown (in thousands):

	April 30,		January 31,
	2014		2014
Due in one year or less	$	64,836	$	17,667
Due in greater than one year		91,772		7,958
Total	$	156,608	$	25,625

Schedule of Fair Values and Gross Unrealized Losses of Available-for-Sale Securities Aggregated by Investment Category

The following table shows the fair values and the gross unrealized losses of these available-for-sale securities aggregated by investment category as of April 30, 2014 (in thousands):

			Gross
	Fair		Unrealized
	Value		Losses
U.S. agency obligations	$	39,197	$	(11	)

The following table shows the fair values and the gross unrealized losses of these available-for-sale securities aggregated by investment category as of January 31, 2014 (in thousands):

			Gross
	Fair		Unrealized
	Value		Losses
Corporate notes and bonds	$	1,403	$	(1	)