Organization and Significant Accounting Policies - Revisions to Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred income taxes (long-term)	$ (171)		$ (169)	$ (703)
Accumulated deficit	(102,495)	$ (102,467)	(102,672)	(92,223)	$ (74,835)
Total shareholders’ equity	$ 34,052		34,172	42,689	58,271
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred income taxes (long-term)			0	0
Accumulated deficit			(102,503)	(91,520)	(74,132)
Total shareholders’ equity			34,341	43,392	58,974
Revision
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred income taxes (long-term)			(169)	(703)
Accumulated deficit			(169)	(703)	(703)
Total shareholders’ equity			$ (169)	$ (703)	$ (703)