Note 2 - Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	As of December 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Loss			Fair Value
Cash and cash equivalents
Cash	$	49,819	$	-	$	-		$	49,819
Money market funds		6,870		-		-			6,870
Total	$	56,689	$	-	$	-		$	56,689
Short-term investments
US Treasury securities	$	39,758	$	*)	$	(27	)	$	39,731
Term bank deposits		40,137		-		-			40,137
Total	$	79,895	$	-	$	(27	)	$	79,868

	As of December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Loss		Fair Value
Cash and cash equivalents
Cash	$	42,175	$	-	$	-	$	42,175
Money market funds		6,140		-		-		6,140
Total	$	48,315	$	-	$	-	$	48,315
Short-term investments
Term bank deposits	$	65,493		-		-	$	65,493
Total	$	65,493	$	-	$	-	$	65,493

Property, Plant and Equipment Estimated Useful Life [Table Text Block]

	%
Computer equipment			33
Office furniture and equipment		14	-	15
Leasehold improvements			Over the shorter of the expected lease term or estimated useful life

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]

	Assets as of December 31, 2017				Liabilities as of December 31, 2016
	Notional Amount		Fair Value		Notional Amount		Fair Value
Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships—included in other current assets and accrued expenses and other short term liabilities	$	1,746	$	163	$	46,116	$	(479	)

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

	Year ended December 31, 2017
	As Reported			Adjustments			Recast for Adoption of ASC 606
Total revenues	$	217,364		$	(1,974	)	$	215,390
Operating loss	$	(13,597	)	$	178		$	(13,419	)
Income taxes	$	(2,459	)	$	(328	)	$	(2,787	)
Net loss	$	(13,694	)	$	(151	)	$	(13,845	)

	Year ended December 31, 2016
	As Reported			Adjustments			Recast for Adoption of ASC 606
Total revenues	$	164,456		$	1,407		$	165,863
Operating loss	$	(15,694	)	$	3,699		$	(11,995	)
Income taxes	$	(1,131	)	$	(182	)	$	(1,313	)
Net loss	$	(17,710	)	$	3,517		$	(14,193	)

	December 31, 2017 Balance Sheet Data
	As Reported		Adjustments			Recast for Adoption of ASC 606
Assets
Current assets:
Prepaid expenses and other current assets	$	7,130	$	9,865		$	16,995
Liabilities and stockholders’ equity
Current liabilities:
Accrued expenses and other short term liabilities	$	42,453	$	1,014		$	43,467
Deferred revenues	$	73,891	$	(227	)	$	73,664
Long-term liabilities:
Deferred revenues	$	7,034	$	130		$	7,164

Schedule of Cash and Cash Equivalents [Table Text Block]

	December 31. 2017		December 31. 2016		December 31. 2015
Cash and cash equivalents	$	56,689	$	48,315	$	49,241
Long term restricted cash included in other assets		547		488		467
Cash, cash equivalents and long term restricted cash shown in the consolidated statement of cash flows	$	57,236	$	48,803	$	49,708