Note 1 - General - Recast Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
License revenues	$ 53,528	$ 39,593
Cost of revenues	6,442	4,693
Gross profit	47,086	34,900
Research and development	15,542	10,409
Sales and marketing	39,972	30,914
General and administrative	7,069	5,509
Total operating expenses	62,583	46,832
Operating loss	(15,497)	(11,932)
Financial income, net	978	469
Loss before income taxes	(14,519)	(11,463)
Income taxes	(527)	(200)
Net loss	(15,046)	(11,663)
Prepaid expenses and other current assets	18,933		$ 14,346
Other assets	7,674		7,243
Deferred Revenue, Current	68,481		73,493
Deferred Revenue, Noncurrent	6,247		6,608
Other liabilities	8,045		7,807
Accumulated deficit	(124,437)		(109,390)
Amortization of deferred commissions	3,325	3,027
Deferred commissions	(2,434)	(2,906)
Deferred revenues	(5,373)	(2,417)
Other long term liabilities	237	(541)
Net cash provided by operating activities	17,444	8,297
Previously Reported [Member]
License revenues		40,380
Cost of revenues		4,672
Gross profit		35,708
Research and development		10,409
Sales and marketing		30,811
General and administrative		5,513
Total operating expenses		46,733
Operating loss		(11,025)
Financial income, net		469
Loss before income taxes		(10,556)
Income taxes		(323)
Net loss		(10,879)
Prepaid expenses and other current assets			7,130
Other assets			973
Deferred Revenue, Current			73,891
Deferred Revenue, Noncurrent			7,034
Other liabilities			6,561
Accumulated deficit			(122,454)
Amortization of deferred commissions
Deferred commissions
Deferred revenues		(3,203)
Other long term liabilities		(418)
Net cash provided by operating activities		8,297
Restatement Adjustment [Member] | Accounting Standards Update 2014-09 [Member]
License revenues		(787)	(1,974)
Cost of revenues		21
Gross profit		(808)
Research and development
Sales and marketing		103
General and administrative		(4)
Total operating expenses		99
Operating loss		(907)
Financial income, net
Loss before income taxes		(907)
Income taxes		123
Net loss		(784)
Prepaid expenses and other current assets			7,216
Other assets			6,270
Deferred Revenue, Current			(398)
Deferred Revenue, Noncurrent			(426)
Other liabilities			1,246
Accumulated deficit			$ 13,064
Amortization of deferred commissions		3,027
Deferred commissions		(2,906)
Deferred revenues		786
Other long term liabilities		(123)
Net cash provided by operating activities
License [Member]
License revenues	25,074	18,092
License [Member] | Previously Reported [Member]
License revenues		19,155
License [Member] | Restatement Adjustment [Member] | Accounting Standards Update 2014-09 [Member]
License revenues		(1,063)
Maintenance [Member]
License revenues	$ 28,454	21,501
Maintenance [Member] | Previously Reported [Member]
License revenues		21,225
Maintenance [Member] | Restatement Adjustment [Member] | Accounting Standards Update 2014-09 [Member]
License revenues		$ 276