Financial Instruments - (Tables)

9 Months Ended

Oct. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Cash Equivalents, Marketable Securities and Restricted Cash

The following tables summarize our cash equivalents, marketable securities and restricted cash by significant investment categories and their classification within the valuation hierarchy at the end of fiscal 2021 and the third quarter of fiscal 2022 (in thousands):

 

	At the End of Fiscal 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash Equivalents		Marketable Securities		Restricted Cash
Level 1
Money market accounts	$	—	$	—	$	—	$	49,984	$	39,440	$	—	$	10,544
Level 2
U.S. government treasury notes	339,253		3,241		(1)		342,493		15,340		327,153		—
U.S. government agencies	56,729		516		—		57,245		—		57,245		—
Corporate debt securities	425,115		4,176		(33)		429,258		—		429,258		—
Foreign government bonds	21,486		307		—		21,793		—		21,793		—
Asset-backed securities	79,924		1,015		—		80,939		—		80,939		—
Total	$	922,507	$	9,255	$	(34)	$	981,712	$	54,780	$	916,388	$	10,544

	At the End of the Third Quarter of Fiscal 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash Equivalents		Marketable Securities		Restricted Cash
Level 1
Money market accounts	$	—	$	—	$	—	$	24,339	$	13,795	$	—	$	10,544
Level 2
U.S. government treasury notes	335,607		1,250		(417)		336,440		—		336,440		—
U.S. government agencies	50,147		170		(21)		50,296		—		50,296		—
Corporate debt securities	484,325		1,263		(950)		484,638		—		484,638		—
Foreign government bonds	14,885		112		(6)		14,991		—		14,991		—
Asset-backed securities	69,273		277		(160)		69,390		—		69,390		—
Municipal bonds	2,440		—		(15)		2,425		—		2,425		—
Total	$	956,677	$	3,072	$	(1,569)	$	982,519	$	13,795	$	958,180	$	10,544

Amortized Cost and Estimated Fair Value

The amortized cost and estimated fair value of our marketable securities are shown below by contractual maturity (in thousands):

	At the End of the Third Quarter of Fiscal 2022
	Amortized Cost		Fair Value
Due within one year	$	386,849	$	388,804
Due in one to five years	565,898		565,486
Due in five to ten years	3,930		3,890
Total	$	956,677	$	958,180

Gross Unrealized Losses and Fair Values

The following table presents gross unrealized losses and fair values for those investments that were in a continuous unrealized loss position at the end of fiscal 2021 and the third quarter of fiscal 2022, aggregated by investment category (in thousands):

	At the End of Fiscal 2021
	Less than 12 months				Greater than 12 months				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. government treasury notes	$	8,301	$	(1)	$	—	$	—	$	8,301	$	(1)
Corporate debt securities	32,996		(33)		—		—		32,996		(33)
Total	$	41,297	$	(34)	$	—	$	—	$	41,297	$	(34)

	At the End of the Third Quarter of Fiscal 2022
	Less than 12 months				Greater than 12 months				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. government treasury notes	$	206,574	$	(417)	$	—	$	—	$	206,574	$	(417)
U.S. government agencies	14,559		(21)		—		—		14,559		(21)
Corporate debt securities	271,555		(950)		—		—		271,555		(950)
Foreign government bonds	1,823		(6)		—		—		1,823		(6)
Asset-backed securities	26,718		(160)		—		—		26,718		(160)
Municipal bonds	2,425		(15)		—		—		2,425		(15)
Total	$	523,654	$	(1,569)	$	—	$	—	$	523,654	$	(1,569)