Stockholders' Equity - Employee Equity Incentive Plans - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended					12 Months Ended									1 Months Ended								12 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Oct. 15, 2011	Sep. 30, 2013 Restricted stock units [Member]	Sep. 30, 2012 Restricted stock units [Member]	Sep. 30, 2011 Restricted stock units [Member]	Sep. 30, 2013 2003 Stock Option Plan [Member]	Sep. 30, 2013 2003 Stock Option Plan [Member] Minimum [Member]	Sep. 30, 2013 2003 Stock Option Plan [Member] Maximum [Member]	Sep. 30, 2013 Performance Based Rsu [Member]	Sep. 30, 2013 Performance RSUs [Member]	Sep. 30, 2013 Common Stock [Member]	Nov. 30, 2012 2005 Equity Incentive Plan [Member]	Nov. 30, 2011 2005 Equity Incentive Plan [Member]	Nov. 30, 2010 2005 Equity Incentive Plan [Member]	Nov. 30, 2009 2005 Equity Incentive Plan [Member]	Nov. 30, 2008 2005 Equity Incentive Plan [Member]	Dec. 31, 2007 2005 Equity Incentive Plan [Member]	Nov. 30, 2006 2005 Equity Incentive Plan [Member]	Nov. 16, 2005 2005 Equity Incentive Plan [Member]	Sep. 30, 2013 2005 Equity Incentive Plan [Member]	Mar. 17, 2005 2005 Equity Incentive Plan [Member]	Sep. 30, 2013 2003 Stock Option Plan [Member] Performance Based Rsu [Member]	Sep. 30, 2013 2003 Stock Option Plan [Member] Performance Based Rsu [Member] Minimum [Member]	Sep. 30, 2013 2003 Stock Option Plan [Member] Performance Based Rsu [Member] Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for future issuance	12,439,448
Shares of common stock reserved for future issuance related to outstanding options and other awards	11,505,566
Shares available for grant	933,882																						933,882
Restricted stocks units outstanding to consultants	221,900
Number of authorized shares of common stock for issuance under 2003 & 2005 plan increased																								500,000
Share based compensation percentage of annual increase under condition in number of shares authorized																							1.00%
Additional authorized shares for issuance															3,040,501	325,000	325,000	325,000	325,000	325,000	317,084	273,417	325,000
Common Stock contractual term														10 years
Period stock options vest quarterly									3 years
Percentage shares vesting on first anniversary date									25.00%																50.00%
Percentage shares vesting quarterly after first anniversary date									75.00%																50.00%
Option grants to employees, description	Stock Options. Stock options are granted with an exercise price equal to the current market price of the Company's common stock at the grant date and have 10-year contractual terms. For option awards, typically 25% of the option shares vest and become exercisable on the first anniversary of the grant date and the remaining 75% of the option shares vest and become exercisable quarterly in equal installments thereafter over three years.
Weighted average grant date fair value of option granted	$ 1.95	$ 1.89	$ 3.18
Total intrinsic value of option exercised based on the differences in market prices	$ 2.2	$ 3.7	$ 2.5
Total unrecognized compensation cost related to unvested options	8.1
Weighted average period for total unrecognized compensation cost related to unvested options	2 years 6 months					2 years 7 months 6 days
Restricted stock units grant to employees, description	RSUs granted to employees generally vest based on three or four years of continuous service from the date of grant. RSUs granted to non-employee directors generally vest over the term of one year from the grant date and are not released until the awardee’s termination of service. Vesting for non-employee director grants allow for accelerated vesting of RSUs in the case of a non-employee director’s resignation where either: (i) he/she has served for at least four years as a member of the Board and is in good standing at the time of resignation, or (ii) he/she resigns for reasons related to health or family matters and is otherwise in good standing at the time of resignation.
Grant fair value of awarded performance based RSU	$ 2.65	$ 2.15	$ 4.12	$ 2.08
Grant date fair value of Restricted Stock Units						1.4	1.2	1.1
Unrecognized compensation cost related to unvested shares						$ 3.1
Vested restricted stock units granted to directors not issued until the director resigns	1,267,215	1,600,564	1,413,481			1,267,215
Shares of restricted stock with a weighted-average grant date fair value, value						$ 2.08
Share based compensation arrangement by share based payment award equity instruments other than options vested but remained restricted in period weighted average grant date fair value						176,839	187,083	255,343
Company awarded performance based RSU												325,436	30,000
Percentage of target in relation to performance goal																										0.00%	100.00%
Vesting period									4 years			3 years
RSUs outstanding	1,637,210	1,016,624										321,436
Restricted stock units balance vesting period									3 years			2 years
Additional performance RSUs outstanding													30,000
Vesting period													4 years
Options grants to employees vest and exercisable on first anniversary of grant date	25.00%
Options grants to employees vest and exercisable in equal installments over next three years	75.00%
Additional actual number of shares to be awarded										0.00%	100.00%
RSU awarded by the right to acquire shares of common stock to non-employee				120,000
Restricted stock re-measured value					$ 3.22