Debt - Future Minimum Payments of Equipment Lease Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
2019	$ 870
2020	45,490
2021	1,049
2022	961
2023	731
Total minimum payments	49,101
Amount representing interest	134
Amount representing unamortized lender fees	(245)
Present value of payments	48,722
Less: current portion	(829)	$ (860)
Long-term debt, net of current portion	47,893	0
Credit Facility
Debt Instrument [Line Items]
2019	0
2020	44,500
2021	0
2022	0
2023	0
Total minimum payments	44,500
Amount representing unamortized lender fees	(245)
Less: current portion	0
Long-term debt, net of current portion	44,255	0
Notes payable
Debt Instrument [Line Items]
2019	739
2020	859
2021	918
2022	830
2023	484
Total minimum payments	3,830
Less: current portion	(739)	(288)
Long-term debt, net of current portion	3,091	0
Capital leases
Debt Instrument [Line Items]
2019	131
2020	131
2021	131
2022	131
2023	247
Total minimum payments	771
Amount representing interest	134
Present value of payments	637
Less: current portion	(90)	(572)
Long-term debt, net of current portion	$ 547	$ 0

Amount necessary to reduce net minimum lease payments to present value for capital leases.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737

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Present value of minimum lease payments for capital leases net of executory costs, including amounts paid by the lessee to the lessor for insurance, maintenance and taxes.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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