Stockholders' Equity

6 Months Ended

Jun. 30, 2022

Share-based Payment Arrangement [Abstract]

10.

Stockholders’ Equity

Stock Options

During the six months ended June 30, 2022, the Company had the following activities under its equity incentive plans:


		Available for Grant			Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Balance at December 31, 2021			5,641,782			6,767,895		$	19.14
	Shares authorized		—			—
	Granted (1)		(2,098,105	)		1,402,398			27.94
	Exercised (2)		—			(693,988	)		10.47
	Forfeited and expired		256,874			(256,874	)		43.56
Outstanding at June 30, 2022			3,800,551			7,219,431		$	20.81		6.08	$	72,849,218
Vested and expected to vest, net of estimated forfeiture at June 30, 2022						6,904,798		$	20.25		5.94	$	72,382,158
Exercisable at June 30, 2022						4,733,359		$	14.10		4.58	$	67,465,870

(1)

The difference between shares granted in the number of shares available for grant and outstanding options represents the RSUs and RSAs granted for the period with a 1.5 share ratio reduction to the reserve shares for each RSU or RSA grant in accordance with the amended and restated 2012 Equity Incentive Award Plan.

(2)

Shares presented as available for grant represents shares repurchased for tax withholding upon vesting of RSUs.

Restricted Stock

During the six months ended June 30, 2022, the activity for restricted stock is summarized as follows:


	Shares			Weighted Average Grant-Date Fair Value
Balance at December 31, 2021		413,510		$	45.94
Granted		463,803			28.29
Vested		(245,840	)		37.28
Unvested at June 30, 2022		631,473		$	36.34

Stock-based Compensation

Total stock-based compensation expense was $8.1 million and $17.6 million during the three and six months ended June 30, 2022, and $7.7 million and $15.8 million during the same periods ended June 30, 2021. As of June 30, 2022, $49.3 million, $15.4 million and $0.2 million of total unrecognized compensation expenses associated with outstanding employee stock options, unvested restricted stock, and the ESPP, net of estimated forfeitures, respectively, were expected to be recognized over a weighted-average period of 2.8, 2.6 and 0.4 years, respectively.