Note 10 - Stock Option Plan (Details) - Summary of Options Outstanding and Exercisable (USD $)	9 Months Ended
	Sep. 30, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number (in Shares)	2,294,535
Options Outstanding, Weighted-Average Exercise Price	$ 1.02
Options Outstanding, Weighted Average Contractual Life (Years)	9 years 244 days
Options Exercisable, Number (in Shares)	413,059
Options Exercisable, Weighted-Average Exercise Price	$ 2.94
Range One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price	$ 0.12
Range of Exercise Price, Upper	$ 0.12
Options Outstanding, Number (in Shares)	320
Options Outstanding, Weighted-Average Exercise Price	$ 0.12
Options Outstanding, Weighted Average Contractual Life (Years)	2 years 76 days
Options Exercisable, Number (in Shares)	320
Options Exercisable, Weighted-Average Exercise Price	$ 0.12
Range Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price	$ 0.60
Range of Exercise Price, Upper	$ 0.60
Options Outstanding, Number (in Shares)	1,901,476
Options Outstanding, Weighted-Average Exercise Price	$ 0.60
Options Outstanding, Weighted Average Contractual Life (Years)	10 years
Options Exercisable, Number (in Shares)	20,000
Options Exercisable, Weighted-Average Exercise Price	$ 0.60
Range Three [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price	$ 1.24
Range of Exercise Price, Upper	$ 1.24
Options Outstanding, Number (in Shares)	314,036
Options Outstanding, Weighted-Average Exercise Price	$ 1.24
Options Outstanding, Weighted Average Contractual Life (Years)	8 years 54 days
Options Exercisable, Number (in Shares)	314,036
Options Exercisable, Weighted-Average Exercise Price	$ 1.24
Range Four [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower	$ 7.00
Range of Exercise Price	$ 9.00
Range of Exercise Price, Upper	$ 9.00
Options Outstanding, Number (in Shares)	59,372
Options Outstanding, Weighted-Average Exercise Price	$ 8.63
Options Outstanding, Weighted Average Contractual Life (Years)	8 years 102 days
Options Exercisable, Number (in Shares)	59,372
Options Exercisable, Weighted-Average Exercise Price	$ 8.63
Range Five [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower	$ 12.00
Range of Exercise Price	$ 18.63
Range of Exercise Price, Upper	$ 18.63
Options Outstanding, Number (in Shares)	19,081
Options Outstanding, Weighted-Average Exercise Price	$ 15.29
Options Outstanding, Weighted Average Contractual Life (Years)	6 years 288 days
Options Exercisable, Number (in Shares)	19,081
Options Exercisable, Weighted-Average Exercise Price	$ 15.29
Range Six [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price	$ 37.00
Range of Exercise Price, Upper	$ 37.00
Options Outstanding, Number (in Shares)	250
Options Outstanding, Weighted-Average Exercise Price	$ 37.00
Options Outstanding, Weighted Average Contractual Life (Years)	3 years 262 days
Options Exercisable, Number (in Shares)	250
Options Exercisable, Weighted-Average Exercise Price	$ 37.00