Cash and Cash Equivalents, Restricted Cash and Short-Term Investments - Summary of Cash, Cash Equivalents, Restricted Cash, and Short-Term Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Cash and Cash Equivalents [Abstract]
Cash	$ 5,090	$ 930
Money market	39,254	9,084
Total cash and cash equivalents	44,344	10,014	23,829	8,896
Corporate bonds		6,191
Total short-term investments	0	6,191
Total restricted cash	250	375
Total	$ 44,594	$ 16,580