Note 4 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	Fair Value Measurements at Reporting Date Using
	March 31, 2015		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash & cash equivalents:
Money market funds	$	64,321,194	$	-	$	64,321,194	$	-
Bank certificates of deposit		2,500,000		-		2,500,000		-
Total cash & cash equivalents	$	66,821,194	$	-	$	66,821,194	$	-
Investments:
Bank certificates of deposit	$	12,500,000	$	-	$	12,500,000	$	-

	Fair Value Measurements at Reporting Date Using
	December 31, 2014		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash & cash equivalents:
Money market funds	$	69,551,754	$	-	$	69,551,754	$	-
Bank certificates of deposit		3,000,000		-		3,000,000		-
Total cash & cash equivalents	$	72,551,754	$	-	$	72,551,754	$	-
Investments:
Bank certificates of deposit	$	6,750,000	$	-	$	6,750,000	$	-