Fair Value Measurements of Assets and Liabilities - Summary of Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($)
$ in Thousands |
Apr. 30, 2017 |
Jan. 31, 2017 |
| Assets: |
|
|
| Assets fair value |
$ 39,059
|
$ 39,025
|
| Corporate Bonds |
|
|
| Assets: |
|
|
| Assets fair value |
17,992
|
16,803
|
| Fair Value, Inputs, Level 1 |
|
|
| Assets: |
|
|
| Assets fair value |
14,073
|
12,491
|
| Fair Value, Inputs, Level 2 |
|
|
| Assets: |
|
|
| Assets fair value |
24,986
|
26,534
|
| Fair Value, Inputs, Level 2 | Corporate Bonds |
|
|
| Assets: |
|
|
| Assets fair value |
17,992
|
16,803
|
| Money Market Funds |
|
|
| Assets: |
|
|
| Cash equivalents |
13,842
|
12,260
|
| Restricted cash |
129
|
129
|
| Money Market Funds | Fair Value, Inputs, Level 1 |
|
|
| Assets: |
|
|
| Cash equivalents |
13,842
|
12,260
|
| Restricted cash |
129
|
129
|
| Bank Certificates of Deposit |
|
|
| Assets: |
|
|
| Restricted cash |
102
|
102
|
| Assets fair value |
3,797
|
5,236
|
| Bank Certificates of Deposit | Fair Value, Inputs, Level 1 |
|
|
| Assets: |
|
|
| Restricted cash |
102
|
102
|
| Bank Certificates of Deposit | Fair Value, Inputs, Level 2 |
|
|
| Assets: |
|
|
| Assets fair value |
3,797
|
5,236
|
| Commercial Paper |
|
|
| Assets: |
|
|
| Assets fair value |
1,197
|
2,493
|
| Commercial Paper | Fair Value, Inputs, Level 2 |
|
|
| Assets: |
|
|
| Assets fair value |
1,197
|
2,493
|
| U.S. Government Agencies |
|
|
| Assets: |
|
|
| Assets fair value |
2,000
|
2,002
|
| U.S. Government Agencies | Fair Value, Inputs, Level 2 |
|
|
| Assets: |
|
|
| Assets fair value |
$ 2,000
|
$ 2,002
|