Income Taxes, Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax Assets [Abstract]
Fixed assets		$ 64	$ 133
Deferred revenue		0	39
Accruals and reserves		147	324
Stock options		196	945
Net operating loss carryforwards		35,254	48,852
Federal and state credits		3,461	3,320
Foreign credits		165	156
Intangible assets		2,442	4,167
Research and development expense		2,542	4,347
Gross deferred tax assets		44,271	62,283
Valuation allowance		(44,100)	(62,079)
Total deferred tax assets		171	204
Deferred Tax Liabilities		(543)	0
Net deferred tax asset			$ 204
Net deferred tax liabilities		$ (372)
Income Tax Disclosure [Line Items]
Federal corporate tax rate		35.00%
Cumulative undistributed earnings of foreign subsidiaries		$ 2,670
Amount of dividend distribution tax		$ 543
Plan [Member]
Income Tax Disclosure [Line Items]
Federal corporate tax rate	21.00%