Note 4 - Stockholder's Equity (Deficiency) (Details) - Options Outstanding Separated into Range of Exercise Price (USD $)	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted average exercise price	$ 10.433	$ 9.697
Options outstanding (in Shares)	4,042,100	4,080,611
Weighted average remaining contractual life	6 years 17 days
Options exercisable (in Shares)	2,578,803
Weighted average remaining contractual life of options exercisable	4 years 118 days
Weighted average exercise price of options exercisable	$ 3.488
Range One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower limit	$ 0.070
Weighted average exercise price	$ 0.812
Exercise price upper limit	$ 0.901
Options outstanding (in Shares)	517,811
Weighted average remaining contractual life	2 years 176 days
Options exercisable (in Shares)	517,811
Weighted average remaining contractual life of options exercisable	2 years 176 days
Weighted average exercise price of options exercisable	$ 0.812
Range Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower limit	$ 1.039
Weighted average exercise price	$ 1.263
Exercise price upper limit	$ 1.576
Options outstanding (in Shares)	1,635,172
Weighted average remaining contractual life	4 years 7 days
Options exercisable (in Shares)	1,635,172
Weighted average remaining contractual life of options exercisable	4 years 7 days
Weighted average exercise price of options exercisable	$ 1.263
Range Three [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower limit	$ 6.230
Weighted average exercise price	$ 6.754
Exercise price upper limit	$ 8.800
Options outstanding (in Shares)	154,818
Weighted average remaining contractual life	6 years 235 days
Options exercisable (in Shares)	126,326
Weighted average remaining contractual life of options exercisable	6 years 207 days
Weighted average exercise price of options exercisable	$ 6.761
Range Four [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted average exercise price	$ 12.470
Options outstanding (in Shares)	387,601
Weighted average remaining contractual life	7 years 338 days
Options exercisable (in Shares)	185,324
Weighted average remaining contractual life of options exercisable	7 years 329 days
Weighted average exercise price of options exercisable	$ 12.470
Range Five [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower limit	$ 21.000
Weighted average exercise price	$ 21.609
Exercise price upper limit	$ 24.230
Options outstanding (in Shares)	1,004,548
Weighted average remaining contractual life	9 years 85 days
Options exercisable (in Shares)	66,556
Weighted average remaining contractual life of options exercisable	8 years 228 days
Weighted average exercise price of options exercisable	$ 21.756
Range Six [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted average exercise price	$ 29.880
Options outstanding (in Shares)	154,200
Weighted average remaining contractual life	9 years 328 days
Range Seven [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted average exercise price	$ 39.860
Options outstanding (in Shares)	187,950
Weighted average remaining contractual life	8 years 358 days
Options exercisable (in Shares)	47,614
Weighted average remaining contractual life of options exercisable	8 years 358 days
Weighted average exercise price of options exercisable	$ 39.860

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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