Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Jul. 31, 2008	$ 130,875	$ 8	$ 249,131	$ (45)	$ (118,219)
Beginning Balance, Shares at Jul. 31, 2008		82,836,000
Comprehensive loss:
Unrealized gain (loss) on short-term investments, net of taxes	227			227
Net income(loss)	(23,413)				(23,413)
Total comprehensive income(loss)	(23,186)
Fair value of shares issued to non-employees	392		392
Fair value of shares issued to non-employees, Shares		69,000
Fair value of stock options issued to non-employees	37		37
Exercise of common stock options	1,943		1,943
Exercise of common stock options, Shares	(1,436,068)	1,436,000
Shares purchased under employee stock purchase plan	3,827		3,827
Shares purchased under employee stock purchase plan, Shares		1,114,000
Repurchase of common stock	449		449
Repurchase of common stock, Shares		(18,000)
Stock-based compensation expense related to stock options and awards issued to employees	24,151	1	24,150
Stock-based compensation expense related to stock options and awards issued to employees, Shares		1,498,000
Repurchase of common stock under stock repurchase program	(991)		(991)
Repurchase of common stock under stock repurchase program, Shares		(191,000)
Excess tax benefit associated with stock based compensation	88		88
Ending Balance at Jul. 31, 2009	137,585	9	279,026	182	(141,632)
Ending Balance, Shares at Jul. 31, 2009		86,744,000
Comprehensive loss:
Unrealized gain (loss) on short-term investments, net of taxes	(84)			(84)
Net income(loss)	(33,998)				(33,998)
Total comprehensive income(loss)	(34,082)
Fair value of shares issued to non-employees	2,385		2,385
Fair value of shares issued to non-employees, Shares		199,000
Fair value of stock options issued to non-employees	32		32
Exercise of common stock options	8,116		8,116
Exercise of common stock options, Shares	(2,974,218)	2,974,000
Shares purchased under employee stock purchase plan	4,515		4,515
Shares purchased under employee stock purchase plan, Shares		1,808,000
Repurchase of common stock	314		314
Repurchase of common stock, Shares		(16,000)
Stock-based compensation expense related to stock options and awards issued to employees	31,683		31,683
Stock-based compensation expense related to stock options and awards issued to employees, Shares		1,897,000
Excess tax benefit associated with stock based compensation	107		107
Ending Balance at Jul. 31, 2010	150,655	9	326,178	98	(175,630)
Ending Balance, Shares at Jul. 31, 2010		93,606,000
Comprehensive loss:
Unrealized gain (loss) on short-term investments, net of taxes	29			29
Net income(loss)	70,688				70,688
Total comprehensive income(loss)	70,717
Fair value of shares issued to non-employees	3,952		3,952
Fair value of shares issued to non-employees, Shares		149,000
Exercise of common stock options	29,752	1	29,751
Exercise of common stock options, Shares	(6,413,368)	6,413,000
Shares purchased under employee stock purchase plan	6,889		6,889
Shares purchased under employee stock purchase plan, Shares		2,048,000
Repurchase of common stock	1		1
Stock-based compensation expense related to stock options and awards issued to employees	54,879		54,879
Stock-based compensation expense related to stock options and awards issued to employees, Shares		1,164,000
Common stock issued in purchase acquisition	28,691		28,691
Common stock issued in purchase acquisition, Shares	1,524,517	1,525,000
Excess tax benefit associated with stock based compensation	(194)		(194)
Ending Balance at Jul. 31, 2011	$ 345,342	$ 10	$ 450,147	$ 127	$ (104,942)
Ending Balance, Shares at Jul. 31, 2011		104,905,000