CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 163,320	$ 306,866
Short-term investments	257,982	156,806
Accounts receivable	10,673	10,496
Receivable from Ionis Pharmaceuticals, Inc.	2,432	3,231
Inventories	13,723	8,817
Other current assets	10,813	10,689
Total current assets	458,943	496,905
Property, plant and equipment, net	5,437	5,261
Operating lease right-of-use assets	10,868	11,094
Intangible assets, net	81,589	83,051
Deposits and other assets	3,084	2,939
Total assets	559,921	599,250
Current liabilities:
Accounts payable	10,372	10,216
Accrued compensation	6,996	12,793
Accrued liabilities	14,131	14,191
Deferred revenue	832	2,165
Other current liabilities	4,001	2,633
Total current liabilities	36,332	41,998
Long-term portion of lease liabilities	13,898	14,248
Total liabilities	50,230	56,246
Stockholders’ equity:
Common stock, $0.001 par value; 125,000,000 shares authorized at March 31, 2020 and December 31, 2019; 101,348,633 and 100,993,173 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively.	101	101
Additional paid-in capital	1,033,319	1,024,168
Accumulated other comprehensive income	391	5
Accumulated deficit	(524,120)	(481,270)
Total stockholders’ equity	509,691	543,004
Total liabilities and stockholders’ equity	$ 559,921	$ 599,250