Stockholders' Equity (Details Textual) - USD ($)					9 Months Ended		57 Months Ended	81 Months Ended
	Sep. 30, 2020	Jun. 30, 2015	Dec. 31, 2013	Nov. 14, 2013	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)					0
Exercises in period, intrinsic value					$ 9,769,000
Compensation cost not yet recognized	$ 0				$ 0		$ 0	$ 0
Restricted Stock Units and Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of Earnings Per Share, amount (in shares)					3,210,930	3,162,815
Convertible Debt
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of Earnings Per Share, amount (in shares)					2,700,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	2 years 4 months 2 days
Compensation cost not yet recognized	$ 156,759,000				$ 156,759,000		$ 156,759,000	$ 156,759,000
The 2005 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance (in shares)			4,713,319
Vesting period (in years)			4 years
Granted (in shares)								0
Shares available for grant (in shares)	0				0		0	0
The 2013 Omnibus Equity Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance (in shares)				1,904,633
Percentage of outstanding stock reserved for grant				4.00%
Percentage of outstanding stock maximum				5.00%
Capital shares reserved for future issuance, annual increase, maximum (in shares)	5,530,555				5,530,555		5,530,555	5,530,555
The 2013 Omnibus Equity Award Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)				4 years
2015 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum employee subscription rate		15.00%
Purchase price of common stock, percent		85.00%
Number of shares authorized (in shares)		500,000
Percent of shares increase, employee stock purchase plan		1.00%
Common stock availability threshold, Employee Stock Purchase Plan		2.00%
Shares increase threshold, employee stock purchase plan (in shares)		400,000
Number of additional shares authorized (in shares)							702,163
Convertible Debt | 2025 Senior Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Initial conversion price (in dollars per share)	$ 92.12				$ 92.12		$ 92.12	$ 92.12