CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue from Contract with Customer, Excluding Assessed Tax	$ 69,510	$ 78,718	$ 81,479
Cost of Goods and Services Sold	17,727	23,164	27,548
Gross profit	51,783	55,554	53,931
Operating expenses:
Research and development	30,789	29,710	29,923
Sales and marketing	21,140	22,953	31,608
General and administrative	20,706	20,996	27,415
Restructuring and other charges	1,873	2,526	1,489
Lease exit and related charges	(454)	0	2,239
Total operating expenses	74,054	76,185	92,674
Operating (loss) income	(22,271)	(20,631)	(38,743)
Other income (expenses):
Interest income, net	344	436	449
Gain (loss) on sale of equity and other investments, net	0	4,500	8,473
Equity in net loss of Napster investment	(757)	(3,991)	(6,533)
Other income (expense), net	(103)	(506)	(643)
Total other income (expenses), net	(516)	439	1,746
Income (loss) from continuing operations before income taxes	(22,787)	(20,192)	(36,997)
Income tax expense (benefit)	2,202	(2,778)	776
Net income (loss) from continuing operations	(24,989)	(17,414)	(37,773)
Income from discontinued operations, net of tax	0	1,109	1,223
Net income (loss)	$ (24,989)	$ (16,305)	$ (36,550)
Income (Loss) from Continuing Operations, Per Basic Share	$ (0.66)	$ (0.47)	$ (1.02)
Basic net income (loss) per common share, Discontinued operations	0.00	0.03	0.03
Net income (loss) per share - basic	(0.66)	(0.44)	(0.99)
Diluted net income (loss) per share, Continuing operations	(0.66)	(0.47)	(1.02)
Diluted net income (loss) per share, Discontinued operations	0.00	0.03	0.03
Net income (loss) per share - diluted	$ (0.66)	$ (0.44)	$ (0.99)
Shares used to compute basic net income (loss) per share	37,582	37,163	36,781
Shares used to compute diluted net income (loss) per share	37,582	37,163	36,781
Comprehensive income (loss):
Unrealized investment holding gains (losses), net of reclassification adjustments	$ 17	$ 8	$ (1,303)
Foreign currency translation adjustments, net of reclassification adjustments	(1,588)	2,090	(862)
Net current period other comprehensive income (loss)	(1,571)	2,098	(2,165)
Net income (loss)	(24,989)	(16,305)	(36,550)
Comprehensive income (loss)	(26,560)	(14,207)	(38,715)
License And Product Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	22,602	28,919	27,846
Cost of Goods and Services Sold	6,109	6,663	6,062
Service Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	46,908	49,799	53,633
Cost of Goods and Services Sold	$ 11,618	$ 16,501	$ 21,486