Under the Company's stock option plan, options, rights and other entitlements be granted to directors, officers, employees and consultants of the Company to purchase up to a maximum of of the total number of outstanding common shares, estimated at million options, rights and other entitlements as at Options are granted at the fair market value of the common shares on the closing trading price of the Company's stock on the day prior to the grant if the grant is made during the trading day or the closing trading price on the day of grant if the grant is issued after markets have closed. Options vest at various rates (immediate to years) and have a term of years.

 

Stock option transactions for the months ended and are summarized as follows:

 

Option numbers are in (000's)
		Three months ended March 31, 2021
		Options				Weighted average exercise price				Weighted average remaining contractual life (years)
Outstanding, beginning of period			11,942			$	4.97
Granted			2,962				4.47
Exercised			(39	)			1.97
Forfeited			(703	)			5.67
Outstanding, end of the period			14,162				4.85				7.1
Exercisable, end of the period			7,887				4.59				5.95
Vested and expected to vest, end of period			13,220				4.83				6.99

 

 

Option numbers are in (000's)
		Three months ended March 31, 2020
		Options				Weighted average exercise price				Weighted average remaining contractual life (years )
Outstanding, beginning of period			5,941			$	2.84
Granted			6,109				6.84
Exercised			(162	)			2.71
Forfeited			(30	)			2.17
Outstanding, end of the period			11,858				4.84				8.6
Exercisable, end of the period			3,990				2.96				6.8
Vested and expected to vest, end of period			10,678				4.73				8.5

 

As of there was million of total unrecognized compensation cost related to non-vested stock options, which is expected to be recognized over an estimated weighted-average period of years.

 

The following table presents the weighted average assumptions that were used in the Black-Scholes option pricing model to determine the fair value of stock options granted during the period, and the resultant weighted average fair values:

 

		Three months ended March 31, 2021				Three months ended March 31, 2020
Risk-free interest rate			0.4	%			1.3	%
Expected dividend yield			-				-
Expected volatility			80.7	%			85.8	%
Expected life of options (years)			5				5
Grant date fair value		$	2.85			$	4.60

 

The Company uses historical data to estimate the expected dividend yield and expected volatility of its common shares in determining the fair value of stock options. The expected life of the options represents the estimated length of time the options are expected to remain outstanding.

 

The following table presents the vesting terms of options granted in the period:

 

Option numbers are in (000's)		Three months ended March 31, 2021				Three months ended March 31, 2020
		Number of options				Number of options
Cliff vesting after one year anniversary			-				300
3 year vesting (50%-25%-25%)			430				862
4 year vesting (50%-16 2/3%-16 2/3%-16 2/3%)			2,532				4,947
Total stock options granted in the period			2,962				6,109

 

 

Restricted share units

 

The Company has a stock incentive plan (SIP) pursuant to which the Board grant stock-based awards comprised of restricted stock units or dividend equivalents to employees, officers, consultants, independent contractors, advisors and non-employee directors of the Company. Each restricted unit is automatically redeemed for common share of the Company upon vesting. The following table presents the activity under the SIP plan for the months ended and and the units outstanding.

 

		Three months ended, March 31, 2021								Three months ended, March 31, 2020
		Number (in thousands)				Weighted average grant date fair value				Number (in thousands)				Weighted average grant date fair value
Outstanding, beginning of period			-			$	-				40			$	2.00
Granted			-				-				645				7.32
Outstanding, end of period			-			$	-				685			$	7.01

 

On the Company granted restricted share units (RSUs) having a vesting term of months. On the vesting term on the RSUs was extended from months to months. On all of these restricted share units were vested and were redeemed for common shares.

 

The grant date fair value of the RSUs was determined as the closing value of the common shares of the Company on the Nasdaq Stock Market on the date prior to the date of grant.

 

 

The Company recorded share-based payment expense related to stock options as follows:

 

		Three months ended March 31, 2021				Three months ended March 31, 2020
Research and development		$	1,378			$	800
General and administrative			5,265				3,601
Total		$	6,643			$	4,401