Balance Sheet Information and Fair Value - Marketable Securities (Detail) - USD ($) $ in Thousands	Feb. 28, 2017	Feb. 29, 2016
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	$ 80,192	$ 36,014
Marketable securities, Gross Unrealized Gains	20	432
Marketable securities, Gross Unrealized Losses	(297)	(52)
Marketable securities, Fair Value	79,915	36,394
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	9,597	4,717
Marketable securities, Gross Unrealized Gains	6	9
Marketable securities, Gross Unrealized Losses	(28)	(3)
Marketable securities, Fair Value	9,575	4,723
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	41,822	19,135
Marketable securities, Gross Unrealized Gains	11	11
Marketable securities, Gross Unrealized Losses	(140)	(22)
Marketable securities, Fair Value	41,693	19,124
Foreign government bonds
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	650	205
Marketable securities, Gross Unrealized Gains	0	0
Marketable securities, Gross Unrealized Losses	(1)	0
Marketable securities, Fair Value	649	205
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	3,324	2,341
Marketable securities, Gross Unrealized Gains	0	0
Marketable securities, Gross Unrealized Losses	(22)	(13)
Marketable securities, Fair Value	3,302	2,328
U.S. government agency securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	12,707	2,242
Marketable securities, Gross Unrealized Gains	1	6
Marketable securities, Gross Unrealized Losses	(77)	(14)
Marketable securities, Fair Value	12,631	2,234
U.S. government notes
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost	12,092	4,279
Marketable securities, Gross Unrealized Gains	2	26
Marketable securities, Gross Unrealized Losses	(29)	0
Marketable securities, Fair Value	$ 12,065	4,305
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Marketable securities, Amortized Cost		3,095
Marketable securities, Gross Unrealized Gains		380
Marketable securities, Gross Unrealized Losses		0
Marketable securities, Fair Value		$ 3,475

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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