Condensed Consolidated Statements of Cash Flows - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Cash flows from operating activities    
Net loss $ (1,199) $ (1,075)
Adjustments to reconcile net loss to net cash provided by operating activities:    
Depreciation and amortization 3,249 3,051
Loss on retirement of assets 9 12
Amortization of deferred financing costs and accretion of interest 55 55
Stock based compensation 4,247 4,831
Provision for doubtful accounts 191 209
Deferred income taxes (4,582) (1,955)
Unrealized currency loss on foreign denominated intercompany transactions (575) 293
Changes in operating assets and liabilities, net of effect of acquisitions:    
Accounts receivable 7,783 4,445
Prepaid expenses and other assets (1,321) (820)
Accounts payable 1,463 (190)
Accrued income taxes (690) (569)
Accrued expenses and other liabilities (4,179) (4,334)
Deferred revenue 3,045 1,628
Net cash provided by operating activities 7,496 5,581
Cash flows from investing activities    
Purchases of property and equipment (1,463) (1,969)
Purchases of intangible assets (160)  
Net cash used in investing activities (1,623) (1,969)
Cash flows from financing activities    
Payments on revolving line of credit (3,000) (3,000)
Common stock dividends paid (4,712) (4,568)
Purchase of treasury stock   (658)
Payments for employee taxes on shares withheld (1,210) (510)
Proceeds from exercises of common stock options 2,648 310
Net cash used in financing activities (6,274) (8,426)
Effect of exchange rates on cash, cash equivalents and restricted cash 943 307
Increase (decrease) in cash, cash equivalents and restricted cash 542 (4,507)
Cash, cash equivalents and restricted cash at beginning of period 100,809 109,427
Cash, cash equivalents and restricted cash at end of period $ 101,351 $ 104,920