Summary of Significant Accounting Policies - Summary of Restricted Cash (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 183	$ 165
Certificates of Deposit [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	5	5
Flexible Spending Funds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	4	8
Fixed Deposit Pledge [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 174	$ 152