Convertible Promissory Notes (Tables)

12 Months Ended

Dec. 31, 2021

Dec. 31, 2020

Debt Disclosure [Abstract]

Summary of convertible promissory notes

Convertible promissory notes—related parties, net of discounts and deferred issuance costs, consisted of the following (in thousands):

	December 31, 2021			December 31, 2020
Convertible notes issued in November 2018	$	125		$	195
Convertible notes issued in October 2020		623			1,022
Unamortized discount and deferred issuance costs		(5	)		(18	)
Total	$	743		$	1,199

Summary of grant date fair value

These instruments were therefore considered share based compensation awards to non-employees, and the instruments were initially measured and recorded at their grant date fair value based on a Black-Scholes option- pricing model.

Volatility	74.0%
Time until maturity	4.96 - 4.97 years
Dividend yield	0%
Risk-free interest rate	(0.63)% - (0.76)%
Conversion payment	€17
Fair value of ordinary shares	€75