Note 1 - Fair Value of Financial Assets and Liabilities (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member]
Assets, fair value	$ 9,228	$ 9,442
Fair Value, Inputs, Level 1 [Member] \| Commercial Paper [Member]
Assets, fair value	29,623	29,686
Fair Value, Inputs, Level 1 [Member]
Assets, fair value	38,851	39,128
Money Market Funds [Member]
Assets, fair value	9,228	9,442
Commercial Paper [Member]
Assets, fair value	29,623	29,686
Assets, fair value	$ 38,851	$ 39,128

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