Note 11 - Stockholders' equity (Detail) (USD $)	1 Months Ended		12 Months Ended			12 Months Ended											12 Months Ended			12 Months Ended				12 Months Ended
	May 27, 2011	Nov. 30, 2006	Dec. 31, 2012	Dec. 31, 2011	Dec. 12, 2007	Dec. 31, 2011 Director [Member] The 2001 Non-Qualified Stock Option Plan [Member]	Dec. 31, 2012 Director [Member] The 2007 Share Incentive Plan [Member]	Dec. 31, 2011 Director [Member] The 2007 Share Incentive Plan [Member]	Dec. 31, 2010 Director [Member] The 2007 Share Incentive Plan [Member]	Dec. 31, 2011 Directors and Key Employees [Member] The 2007 Share Incentive Plan [Member]	Dec. 31, 2012 The 1989 Non-Qualified Stock Option Plan [Member] Minimum [Member]	Dec. 31, 2012 The 1989 Non-Qualified Stock Option Plan [Member] Maximum [Member]	Dec. 31, 2012 The 1989 Non-Qualified Stock Option Plan [Member]	Dec. 31, 2011 The 1989 Non-Qualified Stock Option Plan [Member]	Dec. 31, 2010 The 1989 Non-Qualified Stock Option Plan [Member]	Jun. 15, 1989 The 1989 Non-Qualified Stock Option Plan [Member]	Dec. 31, 2012 The 2001 Non-Qualified Stock Option Plan [Member]	Dec. 31, 2011 The 2001 Non-Qualified Stock Option Plan [Member]	Dec. 31, 2010 The 2001 Non-Qualified Stock Option Plan [Member]	Dec. 31, 2012 The 2007 Share Incentive Plan [Member]	Dec. 31, 2011 The 2007 Share Incentive Plan [Member]	Dec. 31, 2010 The 2007 Share Incentive Plan [Member]	Dec. 31, 2012 Three Plans [Member]	Dec. 31, 2012 Selling, General and Administrative Expenses [Member]	Dec. 31, 2011 Selling, General and Administrative Expenses [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]
Stock Issued During Period, Shares, New Issues	967,950
Share Price (in Dollars per share)	$ 10.50
Proceeds from Issuance of Common Stock (in Dollars)	$ 9,387,666			$ 9,387,666
Common Stock, Capital Shares Reserved for Future Issuance		300,000			750,000											700,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years											4 years
Share-Based Compensation Arrangement by Share-Based Payment Award Expiration											5 years	7 years						10 years			10 years					7 years	10 years
Common Stock, Par or Stated Value Per Share (in Dollars per share)		$ 0.01	$ 0.01	$ 0.01
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross						14,000	8,000	200	16,500	40,400			0	0			0	14,000		0	0
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in Dollars per share)						$ 7.90							$ 0	$ 0			$ 4.25	$ 4.25		$ 11.51
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights																		25%
Share-based Compensation (in Dollars)			234,858	290,598
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number													41,900	102,000	180,250		162,480	170,590	211,300	200	200	200	204,580
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			68,210	131,560									60,100	78,250			8,110	53,310		0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value (in Dollars)			442,907	1,522,715
Allocated Share-based Compensation Expense (in Dollars)																								$ 235,000	$ 291,000