Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Deferred Compensation Arrangement with Individual, Share-based Payments [Table Text Block]

the eight months ended August 31, 2020 and years ended December 31, 2019 and 2018:

	Eight Months Ended August 31,		Year Ended December 31,
Stock-based Compensation	2020		2019		2018
(in thousands)
Employees and directors (1)	$	18,802	$	6,834	$	4,337

Schedule of common stock activity available under share-based compensation plans

The number of shares of common stock authorized for issuance, shares of common stock issued upon exercise of options or grant of restricted stock awards, shares of common stock subject to outstanding awards and shares available for grant under this plan as of December 31, 2020, are as follows:

Title of Plan	Total Shares of Common Stock Authorized	Total Shares of Common Stock Issued	Total Shares of Common Stock Available for Grant
2005 Equity Incentive Plan	26,200,000	17,731,795	8,468,205

Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]

	2020
	Number of shares	Weighted-average grant-date fair value per share
	(in thousands)
Unvested at beginning of year	933	$	3.56
Awards granted	3,044	$	3.10
Awards vested	(2,872)	$	3.14
Withheld related to net settlement	(1,089)	$	3.39
Forfeited	(16)	$	3.22
Unvested at end of year	—	$	—

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The fair value of each stock option grant was estimated on the date of grant using the Black-Scholes option-pricing model. Expected volatility was based on the historical volatility of the Company’s common stock over the estimated expected life of the options. The expected term represents the period of time the options were expected to be outstanding. The expected term is based on the “simplified method” as defined by the SEC Staff Accounting Bulletin No. 110 (Topic 14.D.2). The Company used the “simplified method” due to the lack of sufficient historical exercise data to provide a reasonable basis upon which to otherwise estimate the expected life of the options. The risk-free rate was based on yields on U.S. Treasury securities with a maturity similar to the estimated expected term of the options. The fair value of restricted stock awards was based on the closing price of the Company’s common stock on the grant date.

The fair value of the Company’s stock options granted in the eight months ended August 31, 2020 and the years ended December 31, 2019 and 2018, were estimated assuming no expected dividends and the following weighted-average assumptions:

	Eight Months Ended August 31,	Year Ended December 31,
	2020	2019			2018
Range of expected term (in years)	1.0	3.5	-	6.1	3.5	-	6.0
Range of risk-free interest rate	0.1%	1.5%	-	3.0%	2.7%	-	3.0%
Expected volatility	55%	40%			40%