Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4297-108586

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3367-108585

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (e)
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Debt - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
Debt - Narrative (Details) - USD ($) $ in Thousands	Mar. 02, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Instrument [Line Items]
Repayment of long-term debt				$ 4,999	$ 0
Interest paid on debt		$ 0	$ 152	$ 142	$ 301
Loans Payable \| Secured Debt \| Hercules Technology Growth Capital
Debt Instrument [Line Items]
Repayment of long-term debt	$ 4,999
Payments for debt end term fees	$ 100