Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 144,804				$ 224,868				$ 144,804	$ 224,868
Working capital	(505,500)								(505,500)
Accumulated deficit	(333,938)				(107,168)				(333,938)	(107,168)
Operating income (loss)	(43,980)	$ 8,768	$ (87,366)	$ (65,483)	(195,865)	$ (75,980)	$ (91,166)	$ (25,415)	(188,061)	(388,426)	$ (22,884)
Net (loss)	80,660	$ (47,670)	$ 111,599	$ 82,181	215,038	$ 70,140	$ 87,984	$ 28,747	$ 226,770	401,909	24,550
Contract with customer, payment terms, period									90 days
Noncurrent restricted cash	$ 800				900				$ 800	900
Chargeback period, extended period									84 days
Chargebacks									$ 678,204	$ 830,038	953,326
Sales chargebacks as a percentage of gross sales									40.50%	44.00%
Gross sales									$ 1,674,196	$ 1,887,862	2,351,071
Change in ratio of direct to indirect sales for chargeback reserves used in sensitivity analysis	7.40%								7.40%
Potential increase in chargeback expense based on sensitivity analysis	$ 1,000								$ 1,000
Potential decrease in chargeback expense based on sensitivity analysis	$ 2,600								2,600
Rebates, administrative fees and others									$ 241,548	$ 297,802	476,601
Rebates, administrative and other fees as a percentage of gross sales									14.40%	15.80%
Change in ratio of direct to indirect sales for rebates, administrative and other fees used in sensitivity analysis	7.40%								7.40%
Potential increase in rebates, administrative and other fees expense based on sensitivity analysis	$ 100								$ 100
Potential decrease in rebates, administrative and other fees expense based on sensitivity analysis	400								400
Product returns									$ 30,699	$ 20,162	26,874
Sales returns as a percentage of gross sales									1.80%	1.10%
Change in lag time to process returns for sales returns reserve used in sensitivity analysis									5 months 19 days
Potential increase in sales returns expense based on sensitivity analysis	800								$ 800
Potential decrease in sales returns expense based on sensitivity analysis	700								700
Past due gross accounts receivable									10,000
Past due gross accounts receivable, aged over 60 days									5,800
Provision for inventory obsolescence									28,593	$ 27,341	21,400
Allowance for inventory obsolescence	$ 48,589				$ 46,505				48,589	46,505	34,402
Research and development reserve									3,100	4,000
Depreciation									$ 30,500	$ 29,300	$ 23,700
Shares omitted from the calculation of (loss) per share (in shares)									7.0	5.0	3.6
Minimum
Summary Of Significant Accounting Policies [Line Items]
Chargeback period									28 days
Useful life									1 year
Lease term	1 year								1 year
Maximum
Summary Of Significant Accounting Policies [Line Items]
Chargeback period									42 days
Useful life									30 years
Lease term	10 years								10 years