Note 5 - Stock-Based Compensation (Details) - Restricted Stock Units	1 Months Ended		12 Months Ended		6 Months Ended
	Apr. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013 Restricted Stock Units (RSUs) [Member]
Note 5 - Stock-Based Compensation (Details) - Restricted Stock Units [Line Items]
Balance at December 31, 2012					256,616
Balance at June 30, 2013					211,222
Granted	6,729	14,416	125,133	147,661	21,145
Forfeited					0
Vested					(66,539)