Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 89,093	$ 80,931
Marketable securities	439,528	483,946
Accounts receivable, net	11,813	8,952
Collaboration receivable – related party	2,577	1,539
Collaboration receivable – other	2,033	1,928
Royalty receivable – related party	3,300	2,900
Inventory	9,778	7,331
Prepaid expenses and other current assets	29,152	24,177
Total current assets	587,274	611,704
Marketable securities	84,503	152,929
Operating lease assets	91,440	93,643
Property and equipment, net	33,840	31,472
Financing lease assets	881	993
Other assets	1,800	0
Total assets	799,738	890,741
Current liabilities:
Accounts payable	18,707	21,896
Accrued expenses	39,631	53,142
Deferred revenue – related party	4,748	10,933
Operating lease liabilities	6,466	6,642
Financing lease liabilities	306	273
Total current liabilities	69,858	92,886
Deferred revenue, net of current portion – related party	0	50,580
Operating lease liabilities, net of current portion	104,010	106,074
Financing lease liabilities, net of current portion	571	673
Total liabilities	174,439	250,213
Stockholders’ equity:
Preferred stock, $0.001 par value; 25,000,000 shares authorized; no shares issued or outstanding at March 31, 2020 and December 31, 2019	0	0
Common stock, $0.001 par value; 125,000,000 shares authorized; 68,789,925 and 68,401,105 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively	69	68
Additional paid-in capital	2,181,517	2,156,363
Accumulated other comprehensive income	74	202
Accumulated deficit	(1,556,361)	(1,516,105)
Total stockholders’ equity	625,299	640,528
Total liabilities and stockholders’ equity	$ 799,738	$ 890,741