Fair Value of Financial Assets and Liabilities - Financial Assets and Liabilities That Were Subject to Fair Value Measurement on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified
|
Jun. 30, 2013
|
Sep. 30, 2012
|
Assets: |
|
|
Cash equivalents |
$ 16,978 |
$ 6,471 |
Available for sale securities, fair value |
95,885 |
34,907 |
Assets, Fair Value Disclosure, Total |
112,863 |
41,378 |
Liabilities: |
|
|
Warrant liability |
1,784 |
2,001 |
Liabilities, Fair Value Disclosure, Total |
1,784 |
2,001 |
U.S. Treasury Notes [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
1,008 |
1,015 |
Commercial Paper [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
13,037 |
8,143 |
Corporate Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
73,853 |
25,749 |
U.S. Agency Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
4,537 |
|
Certificate of Deposit [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
3,450 |
|
Level 1 [Member]
|
|
|
Assets: |
|
|
Cash equivalents |
16,978 |
6,471 |
Assets, Fair Value Disclosure, Total |
17,986 |
7,486 |
Liabilities: |
|
|
Warrant liability |
|
|
Liabilities, Fair Value Disclosure, Total |
|
|
Level 1 [Member] | U.S. Treasury Notes [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
1,008 |
1,015 |
Level 1 [Member] | Commercial Paper [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 1 [Member] | Corporate Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 1 [Member] | U.S. Agency Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 1 [Member] | Certificate of Deposit [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 2 [Member]
|
|
|
Assets: |
|
|
Cash equivalents |
|
|
Assets, Fair Value Disclosure, Total |
94,877 |
33,892 |
Liabilities: |
|
|
Warrant liability |
|
|
Liabilities, Fair Value Disclosure, Total |
|
|
Level 2 [Member] | U.S. Treasury Notes [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 2 [Member] | Commercial Paper [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
13,037 |
8,143 |
Level 2 [Member] | Corporate Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
73,853 |
25,749 |
Level 2 [Member] | U.S. Agency Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
4,537 |
|
Level 2 [Member] | Certificate of Deposit [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
3,450 |
|
Level 3 [Member]
|
|
|
Assets: |
|
|
Cash equivalents |
|
|
Assets, Fair Value Disclosure, Total |
|
|
Liabilities: |
|
|
Warrant liability |
1,784 |
2,001 |
Liabilities, Fair Value Disclosure, Total |
1,784 |
2,001 |
Level 3 [Member] | U.S. Treasury Notes [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 3 [Member] | Commercial Paper [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 3 [Member] | Corporate Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 3 [Member] | U.S. Agency Bonds [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|
Level 3 [Member] | Certificate of Deposit [Member]
|
|
|
Assets: |
|
|
Available for sale securities, fair value |
|
|