Schedule II - Valuation and Qualifying Accounts (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Summary of Valuation Allowance [Table Text Block]

	Balance at Beginning of Year		Additions		Deductions		Balance at End of Year
Deferred tax assets valuation allowance
Year ended December 31, 2017	$	31,751	$	617	$	25,126	$	7,242
Year ended December 31, 2016	$	27,616	$	6,755	$	2,620	$	31,751
Year ended December 31, 2015	$	26,046	$	3,327	$	1,757	$	27,616

	Balance at Beginning of Year		Additions		Deductions		Balance at End of Year
Allowance for doubtful accounts receivable
Year ended December 31, 2017	$	21	$	14	$	26	$	9
Year ended December 31, 2016	$	4	$	21	$	4	$	21
Year ended December 31, 2015	$	—	$	4	$	—	$	4