Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($)
shares in Thousands, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Income Statement [Abstract]        
Net revenues $ 37,454 $ 36,243 $ 68,925 $ 67,323
Cost of revenues:        
Cost of revenues 8,277 9,930 15,163 18,941
Amortization expense 4,275 4,438 8,278 8,518
Total cost of revenues 12,552 14,368 23,441 27,459
Research and development expense 2,415 2,598 4,892 5,345
Sales and marketing expense 10,479 10,083 21,123 20,665
General and administrative expense 5,202 4,457 10,417 9,637
Shipping and handling costs 248 404 422 600
Depreciation and amortization expense 1,000 1,036 1,993 2,100
Total costs and expenses 31,896 32,946 62,288 65,806
Income before interest, other income (expense) and income taxes 5,558 3,297 6,637 1,517
Net interest expense (3,626) (4,420) (7,300) (9,158)
Loss on extinguishment of debt   (357)   (570)
Other income, net 260 215 475 430
Income (loss) before income taxes 2,192 (1,265) (188) (7,781)
Income tax expense (186) (23) (304) (94)
Net income (loss) 2,006 (1,288) (492) (7,875)
Other comprehensive loss:        
Amortization of net pension loss 56 21 112 43
Comprehensive income (loss) $ 2,062 $ (1,267) $ (380) $ (7,832)
Net income (loss) per common share:        
Basic $ 0.04 $ (0.03) $ (0.01) $ (0.17)
Diluted $ 0.04 $ (0.03) $ (0.01) $ (0.17)
Average number of common shares and equivalents outstanding:        
Basic 45,498 45,641 45,488 45,663
Diluted 46,698 45,641 45,488 45,663