Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 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 three months ended March 31, 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	—		(0.1	)	5.43					(2.7	)	20.20
Options and RSUs canceled	3.3		(0.1	)	23.38					(3.3	)	20.51
Shares repurchased for tax withholdings on release of restricted stock	1.0		—		—					—		20.19
Restricted stock and options granted	(3.9	)								3.9		18.59
Balance at March 31, 2020	88.3		1.8		$	12.36	6.3	$	12.90	28.6		$	20.25
Vested at March 31, 2020			1.2		$	15.40	5.5	$	6.40	—		$	—
Unvested at March 31, 2020			0.6		$	5.26		$	6.50	28.6		$	20.25

Schedule of pre-tax intrinsic value

The following table summarizes information about the pre-tax intrinsic value of options exercised during the three months ended March 31, 2020 and 2019:

	Three months ended March 31,
	2020		2019
Intrinsic value of options exercised	$	1.8	$	3.1

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	—	%