Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of the income tax expense/(benefit)
U.S. corporate income tax rate (as a percent)		35.00%
Reduction in net deferred tax assets		$ 9,700
Current
Federal		18,288	$ 544	$ 624
State		3,822	78	42
Deferred
Federal		21,493	(39,898)
State		(269)	(1,576)
Income tax (benefit)/expense		43,334	(40,852)	666
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
Income tax expense computed at U.S. Federal statutory tax rate		35,217	17,629	5,114
Permanent items		(2,311)	715	601
State income taxes		2,714	(1,523)	42
Change in valuation allowance			(56,019)	(4,705)
Uncertain income tax position		(1,137)	143	533
Research and development credits		(2,196)	(1,902)	(979)
Other		1,353	105	60
Deferred rate change		9,694
Income tax expense/(benefit)		43,334	(40,852)	666
Research and development credit carryforwards		4,200
Available NOL's		51,000
Research and development credit carryforward available in 2019 to 2020		4,200
Federal income taxes paid			0	0
Accrued penalties related to uncertain tax positions		100
Deferred tax assets:
Net operating loss carryforward		5,072	24,926
Deferred rent credit		211	417
Accrued compensation and non-qualified stock options		7,090	8,128
Deferred financing costs			128
Depreciation and amortization		2,073	706
Research and development credits		3,795	7,119
Capitalized overhead into inventory (UNICAP 263A)		480	1,086
Nonrecourse liability related to sale of future royalties		6,377	11,223
Other		645	878
AMT credit		1,613	1,581
Accrued sales deductions		8,449
Net deferred tax asset		35,805	56,192
Deferred tax liability:
Debt discount on convertible notes			(141)
Infringement legal cost		(10,557)	(13,899)
Depreciation		(264)	(423)
Section 481(a)		(4,141)
Net deferred taxes		20,843	41,729
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance at the beginning of the period	$ 8,859	9,299	9,341	8,964
Gross increases related to prior-year tax positions		947
Gross decreases related to prior-year tax positions			(375)	(5)
Gross increases related to current-year tax positions		1,178	662	646
Gross decreases related to current-year tax positions			(169)	(243)
Change in tax rates		(2,565)	(160)	(21)
Balance at the end of the period		8,859	9,299	$ 9,341
Alternate minimum tax expense on uncertain tax position		0	500
U.S. Federal
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
NOL carryforwards			32,100
NOL carryforwards after tax effect			6,700
Available from 2018 to 2020		32,100
State
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
NOL carryforwards			8,100
NOL carryforwards after tax effect			$ 500
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Tax expense on uncertain tax position		400
Minimum | U.S. Federal
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
Available NOL's utilized per year in future years		7,100
Maximum | U.S. Federal
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
Available NOL's utilized per year in future years		$ 18,400
Forecast
Components of the income tax expense/(benefit)
U.S. corporate income tax rate (as a percent)	21.00%