Leases Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Lease Assets And Lease Liabilities [Line Items]
Operating Lease, Cost	$ 4,808
Operating lease right of use assets	11,128	$ 15,099
Finance Lease, Right-of-Use Asset	1,917
Operating and Finance Lease, Right of Use Asset	13,045
Operating Lease, Liability, Current	4,177
Finance Lease, Liability, Current	1,418
Long-term operating leases, net of current portion	9,767	14,310
Long-term finance leases, net of current portion	27		$ 1,404
Operating and Finance Lease, Lease Liability	15,389
Finance Lease, Right-of-Use Asset, Amortization	2,041
Finance Lease, Interest Expense	140
Sublease Income	(168)
Lease, Cost	6,821
Other assets, noncurrent	614	1,011	1,515
Total assets	146,867	148,864	134,269
Other current liabilities	6,431	6,685	3,569
Total current liabilities	36,417	41,846	38,730
Lease incentive obligation	0	0	2,154
Other long-term liabilities	1,007	1,686	2,343
Total liabilities	47,218	59,246	44,631
Accumulated other comprehensive loss	(1,740)	(1,719)	(1,707)
Stockholders' Equity Attributable to Parent	99,649	89,626	89,638	$ 81,911	$ 86,997
Total liabilities and stockholders' equity	$ 146,867	148,864	134,269
Previous Accounting Guidance [Member]
Lease Assets And Lease Liabilities [Line Items]
Other assets, noncurrent			1,515
Total assets			134,269
Other current liabilities			3,569
Total current liabilities			38,730
Lease incentive obligation			2,154
Other long-term liabilities			2,343
Total liabilities			44,631
Accumulated other comprehensive loss			(1,707)
Stockholders' Equity Attributable to Parent			89,638
Total liabilities and stockholders' equity			$ 134,269
Accounting Standards Update 2016-02
Lease Assets And Lease Liabilities [Line Items]
Operating lease right of use assets		15,099
Long-term operating leases, net of current portion		14,310
Other assets, noncurrent		(504)
Total assets		14,595
Other current liabilities		3,116
Total current liabilities		3,116
Lease incentive obligation		(2,154)
Other long-term liabilities		(657)
Total liabilities		14,615
Accumulated other comprehensive loss		(12)
Stockholders' Equity Attributable to Parent		(12)
Total liabilities and stockholders' equity		$ 14,595