Workforce Reduction - Tabular Disclosure (Details) - USD ($) $ in Thousands		12 Months Ended
Aug. 16, 2018	Dec. 31, 2019	Dec. 31, 2018
Workforce Reduction
Charges		$ 3,620	$ 14,715
Reduction in Workforce, Termination of Lesinurad License Agreement, August 16, 2018
Workforce Reduction
Charges	$ 8,300
Employee severance, benefits and related costs
Workforce Reduction
Balance at beginning of period		2,452	0
Charges		3,198	10,492
Amounts paid		(5,365)	(7,811)
Adjustments		(210)	(229)
Balance at end of period		75	2,452
Employee severance, benefits and related costs \| Reduction in Field-based Workforce, January 30, 2018
Workforce Reduction
Balance at beginning of period		0	0
Charges			2,228
Amounts paid			(2,215)
Adjustments			(13)
Balance at end of period			0
Employee severance, benefits and related costs \| Reduction in Headquarter-based Workforce, June 27, 2018
Workforce Reduction
Balance at beginning of period		696	0
Charges		16	2,881
Amounts paid		(689)	(2,074)
Adjustments		(23)	(111)
Balance at end of period		0	696
Employee severance, benefits and related costs \| Reduction in Workforce, Termination of Lesinurad License Agreement, August 16, 2018
Workforce Reduction
Balance at beginning of period		1,756	0
Charges	5,400	0	5,383
Amounts paid		(1,708)	(3,522)
Adjustments		(48)	(105)
Balance at end of period		0	1,756
Employee severance, benefits and related costs \| Reduction in Workforce, February 7, 2019
Workforce Reduction
Balance at beginning of period		0
Charges		3,182
Amounts paid		(2,968)
Adjustments		(139)
Balance at end of period		75	0
Contract related costs
Workforce Reduction
Balance at beginning of period		433	0
Charges		0	1,265
Amounts paid		(287)	(614)
Adjustments		(42)	(218)
Balance at end of period		104	433
Contract related costs \| Reduction in Workforce, Termination of Lesinurad License Agreement, August 16, 2018
Workforce Reduction
Balance at beginning of period		433	0
Charges	$ 2,900	0	1,265
Amounts paid		(287)	(614)
Adjustments		(42)	(218)
Balance at end of period		$ 104	$ 433

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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