CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue:
Revenue	$ 16,074	$ 163,816
Expenses:
Cost of sales - intangible asset amortization	1,419	1,403
Research and development	17,355	99,619
Selling, general and administrative	46,246	44,602
Total expenses	61,333	137,609
(Loss) income from operations	(45,259)	26,207
Other income (expense):
Investment income	1,771	1,224
Other expense	(130)	(112)
(Loss) income before income tax expense	(43,618)	27,319
Income tax benefit (expense)	768	(132)
Net (loss) income	(42,850)	$ 27,187
Weighted-average shares of common stock outstanding, diluted		94,127,942
Ionis [Member]
Expenses:
Net loss share from commercial activities under arrangement with Ionis Pharmaceuticals, Inc.	$ (7,051)	$ (9,056)
Common Stock [Member]
Other income (expense):
Weighted-average shares of common stock outstanding, basic	101,105,070	90,708,330
Common Stock [Member] | Ionis [Member]
Other income (expense):
Net (loss) income	$ (32,674)	$ 23,846
Net (loss) income per share of common stock, basic	$ (0.42)	$ 0.35
Weighted-average shares of common stock outstanding, basic	77,094,682	68,581,967
Net (loss) income per share of common stock, diluted	$ (0.42)	$ 0.34
Weighted-average shares of common stock outstanding, diluted	77,094,682	68,581,967
Common Stock [Member] | Others [Member]
Other income (expense):
Net (loss) income per share of common stock, basic	$ (0.42)	$ 0.15
Weighted-average shares of common stock outstanding, basic	24,010,388	22,126,363
Net (loss) income per share of common stock, diluted	$ (0.42)	$ 0.15
Weighted-average shares of common stock outstanding, diluted	24,010,388	25,545,975
Product [Member]
Revenue:
Revenue	$ 15,159	$ 6,754
Expenses:
Cost of sales	3,364	1,041
Research and Development and License Revenue Under Collaborative Agreement [Member]
Revenue:
Revenue	$ 915	$ 157,062