CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 486,195	$ 683,287
Short-term investments	1,897,892	1,816,257
Contracts receivable	28,605	63,034
Inventories	22,885	18,180
Other current assets	122,468	139,839
Total current assets	2,558,045	2,720,597
Property, plant and equipment, net	163,952	153,651
Patents, net	26,750	25,674
Long-term deferred tax assets	309,614	305,557
Deposits and other assets	32,552	27,633
Total assets	3,090,913	3,233,112
Current liabilities:
Accounts payable	21,174	16,067
Accrued compensation	16,437	37,357
Accrued liabilities	62,507	66,769
Income taxes payable	32,946	32,514
Current portion of long-term obligations and other current liabilities	4,150	2,026
Current portion of deferred contract revenue	120,811	118,272
Total current liabilities	258,025	273,005
Long-term deferred contract revenue	467,842	490,060
Long-term obligations, less current portion	15,043	15,543
Long-term mortgage debt	59,930	59,913
Total liabilities	1,520,502	1,548,565
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 139,282,168 and 140,339,615 shares issued and outstanding at March 31, 2020 (unaudited) and December 31, 2019, respectively	139	140
Additional paid-in capital	2,233,644	2,203,778
Accumulated other comprehensive loss	(27,235)	(25,290)
Accumulated deficit	(846,309)	(707,534)
Total Ionis stockholders' equity	1,360,239	1,471,094
Noncontrolling interest in Akcea Therapeutics, Inc.	210,172	213,453
Total stockholders' equity	1,570,411	1,684,547
Total liabilities and stockholders' equity	3,090,913	3,233,112
0.125 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes	439,996	434,711
1 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes	$ 279,666	$ 275,333