Marketable Securities and Fair Value Measurements - Schedule of Fair Value Measured on Recurring Basis (Detail) - USD ($)
$ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
$ 58,295
|
$ 91,316
|
| Money Market Instruments [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
18,361
|
91,316
|
| Certificates of Deposit [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
14,887
|
|
| United States Treasury Notes [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
25,047
|
|
| Level 2 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
58,295
|
91,316
|
| Level 2 [Member] | Money Market Instruments [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
18,361
|
$ 91,316
|
| Level 2 [Member] | Certificates of Deposit [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
14,887
|
|
| Level 2 [Member] | United States Treasury Notes [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value measurements, cash equivalents and marketable securities |
$ 25,047
|
|