The following is a reconciliation of the numerator (net loss) and the denominator (number of shares) used in the basic and diluted net loss per share calculations:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2021			2020			2021			2020
Net loss attributable to common stockholders	$	(6,155	)	$	(4,763	)	$	(15,699	)	$	(12,946	)
Weighted average number of shares of common stock		9,439			7,465			9,308			3,202
Basic and diluted net loss per share	$	(0.65	)	$	(0.64	)	$	(1.69	)	$	(4.04	)

The Company applied the two-class method for calculating net loss per share. The two-class method is an allocation of losses between the holders of common stock and the Company’s participating securities. Net loss attributable to common stockholders is computed by deducting the dividends accumulated for the period on the Series A Preferred Stock from the Company’s net loss. Interest expense on the Series A Preferred Stock is calculated using the effective interest method. The adjustment, if any, to the net loss is the portion of the cumulative dividends in excess of the interest expense on the Series A Preferred Stock. There were no cumulative dividends in excess of interest expense during the three and nine months ended September 30, 2021 and 2020.

The Company’s basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period.

As the Company has reported a net loss for all periods presented, basic and diluted net loss per share attributable to common stockholders are the same for those periods. The Company excluded 1,452 shares of underlying unvested restricted stock awards and 652 outstanding stock options for the three and nine months ended September 30, 2021 and 1,847 shares of underlying unvested restricted stock awards and 0 outstanding stock options for the three and nine months ended September 30, 2020 from its net loss per diluted share calculations because their effect was anti-dilutive.

The anti-dilutive weighted average shares excluded from the net loss per share diluted shares calculations were:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Restricted stock awards		1,097		1,426		1,190		479
Outstanding stock options		649		—		436		—
Total		1,746		1,426		1,626		479