Supplemental Balance Sheet Information - Other noncurrent liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Supplemental Balance Sheet Information [Abstract]
Operating lease liability	$ 226
Other	0		$ 39
Other noncurrent liabilities	$ 226	$ 381	$ 39

Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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Period Type:	instant

- Definition

Amount of expenses incurred but not yet paid classified as other, due after one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer.

+ References

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- Definition

Supplemental Balance Sheet Information [Abstract]

+ References

No definition available.

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