Fair Value Measurements (Details) - Recurring basis - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Money market funds
Assets
Cash and cash equivalents, fair value	$ 25,629	$ 50,682
Certificates of deposit
Assets
Cash and cash equivalents, fair value	3,922	5,962
Level 1 \| Money market funds
Assets
Cash and cash equivalents, fair value	25,629	50,682
Level 1 \| Certificates of deposit
Assets
Cash and cash equivalents, fair value	$ 3,922	$ 5,962

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant