Fair Value Measurement of Assets and Liabilities - Summary of Company's Financial Instruments, Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Cash equivalents
Total cash equivalents	$ 2,115	$ 2,114
Money market funds
Cash equivalents
Total cash equivalents	645	1,134
Certificates of deposit
Cash equivalents
Total cash equivalents	1,470	980
Level 1
Cash equivalents
Total cash equivalents	645	1,134
Level 1 | Money market funds
Cash equivalents
Total cash equivalents	645	1,134
Level 1 | Certificates of deposit
Cash equivalents
Total cash equivalents	0	0
Level 2
Cash equivalents
Total cash equivalents	1,470	980
Level 2 | Money market funds
Cash equivalents
Total cash equivalents	0	0
Level 2 | Certificates of deposit
Cash equivalents
Total cash equivalents	$ 1,470	$ 980