Note 4 - Stockholder's Equity (Deficiency) - Summary of Employees' Stock Options Activities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Options outstanding at the beginning of the year (in shares)	3,968,238	4,080,611
Options outstanding at the beginning of the year (in dollars per share)	$ 10.515	$ 9.697
Options outstanding at the beginning of the year	$ 50,482	$ 95,855
Options outstanding at the beginning of the year	5 years 317 days	6 years 33 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	191,200
Granted (in dollars per share)	$ 28.253
Exercised (in shares)	(202,771)
Exercised (in dollars per share)	$ 2.936
Forfeited (in shares)	(100,802)
Forfeited (in dollars per share)	$ 26.269
Vested and expected to vest (in shares)	3,874,985
Vested and expected to vest (in dollars per share)	$ 10.20
Vested and expected to vest	$ 50,352
Vested and expected to vest	5 years 289 days
Options exercisable at the end of the period (in shares)	2,649,977
Options exercisable at the end of the period (in dollars per share)	$ 4.414
Options exercisable at the end of the period	$ 47,928
Options exercisable at the end of the period	4 years 132 days