Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2020

Stockholders' Equity Note [Abstract]

Schedule of Stock Option and Restricted Stock Activity

Stock option and restricted stock activity for the Plans was as follows for the six months ended June 30, 2020:

			Options outstanding							Restricted stock outstanding
	Number of shares available for issuance under the Plans		Number of shares outstanding under the Plans		Weighted- average exercise price per share		Weighted- average remaining contractual term (In years)	Aggregate intrinsic value		Number of shares outstanding under the Plans		Weighted- average grant date fair value per share
Balance at December 31, 2019	66.2		2.0		$	12.28	6.5	$	16.40	30.7		$	20.48
Additional shares authorized	21.7		—		—		—	—		—		—
Options exercised and RSUs released	—		(0.3	)	4.77		—	—		(6.1	)	20.01
Options and RSUs canceled	5.9		(0.2	)	17.40		—	—		(5.8	)	20.25
Shares repurchased for tax withholdings on release of restricted stock units and awards	2.2		—		—		—	—		—		20.00
Restricted stock and options granted	(20.8	)	—		—		—	—		20.8		18.64
Balance at June 30, 2020	75.2		1.5		$	13.37	6.2	$	12.70	39.6		$	19.62
Vested at June 30, 2020			1.0		$	16.47	5.5	$	6.30	—		$	—
Unvested at June 30, 2020			0.5		$	5.55		$	6.40	39.6		$	19.62

Schedule of Pre-Tax Intrinsic Value

The following table summarizes information about the pre-tax intrinsic value of options exercised during the three and six months ended June 30, 2020 and 2019:

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Intrinsic value of options exercised	$	3.0	$	1.4	$	4.8	$	4.5

Fair Value of Stock Options Assumptions Used

The fair value of stock options assumed were estimated using the following assumptions:

Expected volatility	51.6	%
Expected term (in years)	3.4 - 7.0
Risk-free interest rate	2.42% - 2.51%
Dividend yield	—	%