Stock option activity for the three months ended April 30, 2022 was as follows:


	Number of Shares	Weighted Average Exercise Price
Outstanding, January 31, 2022	2,629,109	$	6.72
Granted	—	—
Expired or forfeited	(8,812)	14.34
Exercised	(156,975)	4.95
Outstanding, April 30, 2022	2,463,322	$	6.80
Exercisable, April 30, 2022	2,197,707	$	5.78
Fully vested or expected to vest, April 30, 2022	2,436,761	$	6.71

As of April 30, 2022, there was $0.7 million of total unrecognized compensation expense related to unvested stock-based compensation arrangements under the 2014 Stock Plan ("2014 Plan") and 2019 Equity Incentive Plan (as amended and restated, "2019 Plan"). That cost is expected to be recognized over a weighted average period of 0.91 years.

RSU activity during the three months ended April 30, 2022 was as follows:


	Number of Shares	Weighted Average Grant Date Fair Value
Nonvested, January 31, 2022	3,012,440	$	45.62
Granted	1,355,616	46.87
Vested	(193,044)	64.86
Forfeited	(103,887)	45.03
Nonvested, April 30, 2022	4,071,125	$	45.14

As of April 30, 2022, total unrecognized compensation expense related to non-vested RSUs was $154.7 million, adjusted for estimated forfeitures, based on the estimated fair value of the Company’s common stock at the time of grant. That cost is expected to be recognized over a weighted average period of 3.48 years.

The first offering period for the Employee Stock Purchase Plan ("ESPP") began on July 1, 2021 and ended on December 31, 2021. Thereafter, offering periods will begin on January 1 and July 1.

The fair value of ESPP shares during the three months ended April 30, 2022 was estimated at the date of grant using the Black-Scholes option valuation model based on assumptions as follows for ESPP awards: (i) expected life of 0.5 years, (ii) expected volatility of 49.65%, (iii) expected dividends of 0.00%, (iv) risk-free interest rate of 0.22%.

As of April 30, 2022, total unrecognized compensation expense related to the ESPP was $0.3 million. That cost is expected to be recognized over the remaining term of the offering period that began on January 1, 2022 and will end on June 30, 2022.

Total stock-based compensation expense included in our consolidated statements of operations were as follows:


	Three Months Ended April 30,
	2021		2022
Cost of subscription revenues	$	285	$	376
Cost of professional services and other revenues	1,332		1,871
Sales and marketing	1,753		3,371
Research and development	1,543		2,832
General and administrative	2,151		4,850
Total stock-based compensation expense	$	7,064	$	13,300