Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 70,778	$ 56,689
Short-term investments	82,892	79,868
Trade receivables (net of allowance for doubtful accounts of $433 at March 31, 2018 and December 31, 2017)	32,468	75,596
Prepaid expenses and other current assets	18,933	14,346
Total current assets	205,071	226,499
Long-term assets:
Other assets	7,674	7,243
Property and equipment, net	12,180	11,896
Total long-term assets	19,854	19,139
Total assets	224,925	245,638
Current liabilities:
Trade payables	483	635
Accrued expenses and other short term liabilities	36,190	42,453
Deferred Revenue, Current	68,481	73,493
Total current liabilities	105,154	116,581
Long-term liabilities:
Deferred revenues	6,247	6,608
Other liabilities	8,045	7,807
Total long-term liabilities	14,292	14,415
Stockholders’ equity:
Common stock of $0.001 par value - Authorized: 200,000,000 shares at March 31, 2018 and December 31, 2017; Issued and outstanding: 28,748,631 shares at March 31, 2018 and 28,146,162 shares at December 31, 2017	29	28
Accumulated other comprehensive income (loss)	(1,973)	136
Additional paid-in capital	231,860	223,868
Accumulated deficit	(124,437)	(109,390)
Total stockholders’ equity	105,479	114,642
Total liabilities and stockholders’ equity	$ 224,925	$ 245,638