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Noncash Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation Expense

Noncash share-based compensation expense is allocated to expense categories on the Consolidated Statements of Comprehensive Income (Loss). The following table summarizes noncash share-based compensation expense, net of amounts capitalized, for the years ended December 31, 2018, 2017 and 2016 (in thousands).

	For the Year Ended December 31,
	2018				2017				2016
Share-based compensation:
Cost of revenue	$	1,721			$	1,971			$	2,267
Operating expenses:
Selling and marketing	4,396				4,348				3,824
General and administrative	10,717				11,163				9,040
Research and development	4,619				5,314				5,335
Total included in operating expenses	19,732				20,825				18,199
Total share-based compensation expense	$	21,453			$	22,796			$	20,466

Share-based Compensation, Stock Options, Activity [Table Text Block]

The following table summarizes the Company’s stock option activity for the year ended December 31, 2018 (number of shares and intrinsic value in thousands):

	Number of  shares under option			Weighted  average exercise price				Weighted  average remaining  contractual term (year)		Aggregate intrinsic value (1)
Outstanding, December 31, 2017	135			$	12.52
Granted	—			—
Exercised	(135)			12.52
Forfeited	—			—
Expired	—			—
Outstanding, December 31, 2018	—			$	—			0		$	—
Vested and exercisable at December 31, 2018	—			$	—			0		$	—

(1) The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock on December 31, 2018 of $31.40 and the grant date fair value.

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value [Table Text Block]

The following table summarizes the Company's SARs activity for the year ended December 31, 2018 (number of shares and intrinsic value in thousands):

	Stock  appreciation rights			Weighted  average exercise price				Weighted  average remaining  contractual term (year)		Aggregate intrinsic value  (1)
Outstanding, December 31, 2017	356			$	10.97
Granted	—			—
Exercised	(69	)		11.17
Forfeited	—			—
Expired	—			—
Outstanding, December 31, 2018	287			$	10.92			1.86		$	5,869
Exercisable at December 31, 2018	287			$	10.92			1.86		$	5,869
Vested and expected to vest at December 31, 2018	287			$	10.92			1.86		$	5,869

(1) The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock on December 31, 2018 of $31.40 and the exercise price of the underlying SARs.

Schedule of Nonvested Performance-based Units Activity [Table Text Block]

The following table summarizes the Company's MSUs activity for the year ended December 31, 2018 (number of shares and intrinsic value in thousands):

	Number of  unvested awards			Weighted  average grant date fair value				Weighted  average remaining  contractual term (year)		Aggregate intrinsic value (1)
Unvested at December 31, 2017	387			$	23.48
Granted	117			38.18
Exercised	(85	)		31.83
Forfeited	—			—
Expired	—			—
Unvested at December 31, 2018	419			$	25.90			1.10		$	13,162

(1) The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock on December 31, 2018 of $31.40 and the grant date fair value of the underlying MSUs.

Fair value assumptions - market-based RSUs [Table Text Block]

The assumptions used to value the market-based RSUs granted in 2016 were as follows:

		December 31, 2016
Volatility		44.98%
Risk-free interest rate		1.08%
Dividend yield		—

The fair value of the market-based RSUs is expensed over the derived service period for each separate vesting tranche. The derived service period for the vesting tranches of the market-based RSUs ranges between 1.01 and 1.98 years.

Market Stock Units Valuation Assumptions [Table Text Block]

Significant assumptions used in the Monte Carlo simulation model for MSUs granted during the years ended December 31, 2018, 2017 and 2016 are as follows:

	For the Year Ended December 31,
	2018		2017		2016
Volatility	43.67%		45.38%		44.06%
Risk-free interest rate	2.12%		1.56%		1.04%
Expected option life in years	2.97		3.07		2.93
Dividend yield	—		—		—

The assumptions related to fiscal year 2017 are presented on a weighted average basis for the various awards granted throughout the period.

Restricted Stock Unit - time based [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

The following table summarizes the Company's unvested time-based RSUs as of December 31, 2018, and changes during the year then ended (number of shares and intrinsic value in thousands):

	Number of shares			Weighted  average grant date fair value				Weighted  average remaining  contractual term (year)		Aggregate intrinsic value  (1)
Unvested at December 31, 2017	2,133			$	18.90
Granted	829			27.61
Vested	(792	)		20.49
Forfeited	(201	)		20.45
Unvested at December 31, 2018	1,969			$	21.77			2.02		$	61,827
Expected to vest at December 31, 2018	1,902			$	21.65			2.00		$	59,731

(1) The aggregate intrinsic value was calculated based on the fair value of the Company’s common stock on December 31, 2018 of $31.40.

Restricted stock unit - market-based [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

The following table summarizes the Company's unvested market-based RSUs as of December 31, 2018, and changes during the year then ended (number of shares and intrinsic value in thousands):

	Number of shares			Weighted  average grant date fair value				Weighted  average remaining  contractual term (year)		Aggregate intrinsic value  (1)
Unvested at December 31, 2017	345			$	10.86
Granted	—			—
Vested	(115	)		12.61
Forfeited	(15	)		9.98
Unvested at December 31, 2018	215			$	9.98			1.69		$	6,751
Expected to vest at December 31, 2018	211			$	9.98			1.69		$	6,611

(1) The aggregate intrinsic value was calculated based on the fair value of the Company’s common stock on December 31, 2018 of $31.40.

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