Note 6 - Stock-Based Compensation (Details) - Stock Options Outstanding (USD $)	12 Months Ended					3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2014 Range 1 [Member]	Dec. 31, 2014 Range 1 [Member]	Mar. 31, 2014 Range 2 [Member]	Dec. 31, 2014 Range 2 [Member]	Mar. 31, 2014 Range 3 [Member]	Dec. 31, 2014 Range 3 [Member]	Mar. 31, 2014 Range 4 [Member]	Dec. 31, 2014 Range 4 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower Exercise Price						$ 5.76		$ 8.01		$ 10.01		$ 20.01
Upper Exercise Price						$ 8.00		$ 10.00		$ 20.00		$ 33.44
Stock Options Outstanding (in Shares)		502,789	501,334	657,005	722,155	237,969		64,450		109,994		90,376
Weighted-Average Exercise Price		$ 11.18	$ 10.34	$ 10.32	$ 10.18	$ 5.76		$ 9.72		$ 12.55		$ 24.79
Weighted-Average Remaining Contractual Life	3 years 284 days						4 years 284 days		266 days		3 years 197 days		3 years 219 days