Note 4 - Investments (Details Textual)		1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 23, 2015	Jan. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
NKD Enterprises LLC [Member]
Equity Method Investment, Ownership Percentage			25.50%	25.50%	25.50%	25.50%
Equity Method Investment, Other than Temporary Impairment			$ 792,000
Lancope, Inc. [Member] | Subsequent Event [Member]
Proceeds from Sale of Other Investments		$ 2,248,000
Lancope, Inc. [Member]
Cost-method Investments, Realized Gain (Loss), Excluding Other than Temporary Impairments				$ 2,034,000
Cost Method Investments			214,000	214,000	$ 214,000
Held Escrow Period					1 year 180 days
Estimated Portion of Escrow			390,000	390,000	$ 390,000
Equity Method Investment, Other than Temporary Impairment					792,000
Number of Investee Companies	1
Cost-method Investments, Realized Gain (Loss), Excluding Other than Temporary Impairments					2,034,000	$ 145,000
Cost Method Investments			$ 1,015,000	$ 1,015,000	$ 1,015,000	$ 1,605,000