Note 5 - Warranty and Service Contracts (Tables)

12 Months Ended

Dec. 31, 2014

Product Warranties Disclosures [Abstract]

Schedule of Product Warranty Liability [Table Text Block]

	December 31,
	2014			2013
Balance at beginning of year	$	1,202		$	1,212
Add: Accruals for warranties issued during the year		2,497			3,420
Less: Settlements made during the year		(2,532	)		(3,430	)
Balance at end of year	$	1,167		$	1,202

Deferred Revenue, by Arrangement, Disclosure [Table Text Block]

	December 31,
	2014			2013
Balance at beginning of year	$	11,637		$	8,539
Add: Payments received		13,913			15,026
Less: Revenue recognized		(12,601	)		(11,928	)
Balance at end of year	$	12,949		$	11,637