Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-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

Commitments and Contingencies - Leases and Purchase Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Capital Lease Obligations
2020	$ 86
2021	80
2022	71
2023	58
2024	30
Thereafter	0
Total minimum lease payments	325
Less: imputed interest (4.1% to 15.9%)	(34)
Total capital lease obligations	291
Less: current portion of capital lease obligations	(72)	$ (44)
Long-term capital lease obligations	219
Operating Lease Obligations
2020	1,878
2021	1,813
2022	1,817
2023	1,840
2024	1,353
Thereafter	5,167
Total operating lease payments	13,868
Purchase Commitments
2020	22,684
2021	21,418
2022	0
2023	0
2024	0
Thereafter	0
Purchase commitments, total	44,102
Rent expense	$ 2,700	$ 1,700	$ 1,000
Minimum
Capital Lease Obligations
Interest rate	4.10%
Maximum
Capital Lease Obligations
Interest rate	15.90%