CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 633,059	$ 683,287
Short-term investments	1,696,145	1,816,257
Contracts receivable	38,977	63,034
Inventories	22,172	18,180
Other current assets	146,628	139,839
Total current assets	2,536,981	2,720,597
Property, plant and equipment, net	181,518	153,651
Patents, net	28,274	25,674
Long-term deferred tax assets	307,737	305,557
Deposits and other assets	41,191	27,633
Total assets	3,095,701	3,233,112
Current liabilities:
Accounts payable	16,222	16,067
Accrued compensation	28,390	37,357
Accrued liabilities	80,750	66,769
Income taxes payable	8,929	32,514
Current portion of long-term obligations and other current liabilities	5,849	2,026
Current portion of deferred contract revenue	104,431	118,272
Total current liabilities	244,571	273,005
Long-term deferred contract revenue	429,931	490,060
Long-term obligations, less current portion	15,884	15,543
Long-term mortgage debt	59,966	59,913
Total liabilities	1,489,317	1,548,565
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 139,793,901 and 140,339,615 shares issued and outstanding at September 30, 2020 (unaudited) and December 31, 2019, respectively	140	140
Additional paid-in capital	2,311,679	2,203,778
Accumulated other comprehensive loss	(19,572)	(25,290)
Accumulated deficit	(909,098)	(707,534)
Total Ionis stockholders' equity	1,383,149	1,471,094
Noncontrolling interest in Akcea Therapeutics, Inc.	223,235	213,453
Total stockholders' equity	1,606,384	1,684,547
Total liabilities and stockholders' equity	3,095,701	3,233,112
0.125 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes	450,386	434,711
1 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes	$ 288,579	$ 275,333