Note 9 - Convertible Promissory Notes, Related Parties	12 Months Ended
Dec. 31, 2020
Notes to Financial Statements
Convertible Promissory Notes, Related Party [Text Block]	NOTE 9. Convertible Promissory Notes, Related Parties On December 10, 2014, the Company entered into a note purchase agreement with certain existing preferred stockholders under which the Company issued convertible promissory notes during December 2014 for total proceeds of $18.4 million. On November 20, 2015, the Company entered into a second note purchase agreement with certain existing preferred stockholders under which the Company issued convertible promissory notes during November and December 2015 for total proceeds of $11.0 million. These notes were issued with the same terms as the notes issued in 2014. As the holders of the convertible promissory notes each had an equity ownership in the Company, the convertible promissory notes were considered to be a related-party transaction. The convertible promissory notes bore interest at a rate of 8.0% per annum. As of December 31, 2017, the balance of the convertible promissory notes was $35.3 million, comprising principal of $29.4 million plus accrued interest associated with the convertible promissory notes of $6.3 million, offset by unamortized debt discount of $0.4 million. Interest expense related to the convertible promissory notes, including amortization of debt discount, totaled $0.3 million in the year ended December 31, 2018, all related to the 43 days prior to the Merger. On February 13, 2018, the balance of the convertible promissory notes was $35.6 million, comprising principal of $29.4 million plus accrued interest of $6.6 million, offset by the unamortized debt discount to $0.4 million. On that date, in conjunction with the Merger, the convertible promissory notes were exchanged for 1,571,702 shares of the Company's common stock which, based on the closing stock price of $9.05, had a value of $14.2 million. The difference of $21.4 million was recorded as a capital contribution.

NOTE

Convertible Promissory Notes, Related Parties

December

10,

2014,

the Company entered into a note purchase agreement with certain existing preferred stockholders under which the Company issued convertible promissory notes during

December

2014

for total proceeds of

$18.4

million.

November

20,

2015,

the Company entered into a

second

note purchase agreement with certain existing preferred stockholders under which the Company issued convertible promissory notes during

November

and

December

2015

for total proceeds of

$11.0

million. These notes were issued with the same terms as the notes issued in

2014.

As the holders of the convertible promissory notes each had an equity ownership in the Company, the convertible promissory notes were considered to be a related-party transaction.

The convertible promissory notes bore interest at a rate of

8.0%

per annum.

As of

December 31, 2017,

the balance of the convertible promissory notes was

$35.3

million, comprising principal of

$29.4

million plus accrued interest associated with the convertible promissory notes of

$6.3

million, offset by unamortized debt discount of

$0.4

million. Interest expense related to the convertible promissory notes, including amortization of debt discount, totaled

$0.3

million in the year ended

December 31, 2018,

all related to the

days prior to the Merger.

February

13,

2018,

the balance of the convertible promissory notes was

$35.6

million, comprising principal of

$29.4

million plus accrued interest of

$6.6

million, offset by the unamortized debt discount to

$0.4

million. On that date, in conjunction with the Merger, the convertible promissory notes were exchanged for

1,571,702

shares of the Company's common stock which, based on the closing stock price of

$9.05,

had a value of

$14.2

million. The difference of

$21.4

million was recorded as a capital contribution.