Fair Value Measurements - Assets and Liabilities at Fair Value Changes in Level 3 Liabilities (Details) - Fair value on a recurring basis $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Warrant liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Issuance of redeemable preferred stock and warrants	$ 2,643
Change in the fair value of liability	598
Ending balance	3,241
Future tranche right liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Issuance of redeemable preferred stock and warrants	35,472
Change in the fair value of liability	10,964
Ending balance	$ 46,436

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- Definition

Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Amount of issuances of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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