Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets:
Total assets	$ 38,524	$ 18,415
Liabilities:
Contingent acquisition consideration	878	2,302
Total liabilities	878	2,302
Money Market Funds [Member]
Assets:
Cash equivalents	38,524	832
Commercial Paper [Member]
Assets:
Cash equivalents		8,998
Corporate Bonds [Member]
Assets:
Cash equivalents		8,585
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Total assets	38,524	832
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money Market Funds [Member]
Assets:
Cash equivalents	38,524	832
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Total assets		17,583
Significant Other Observable Inputs (Level 2) [Member] | Commercial Paper [Member]
Assets:
Cash equivalents		8,998
Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds [Member]
Assets:
Cash equivalents		8,585
Significant Unobservable Inputs (Level 3) [Member]
Liabilities:
Contingent acquisition consideration	878	2,302
Total liabilities	$ 878	$ 2,302