Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 808,591	$ 370,829
Short-term investments	294,478	803,083
Accounts receivable	56,981	49,044
Inventory	156,569	125,445
Other current assets	110,799	77,782
Total current assets	1,427,418	1,426,183
Property and equipment, net of accumulated depreciation of $38,398 and $28,149 as of June 30, 2019, and December 31, 2018, respectively	117,201	97,024
Intangible assets, net of accumulated amortization of $4,685 and $3,852 as of June 30, 2019, and December 31, 2018, respectively	11,825	11,574
Right of use asset, net	39,449
Other assets	151,860	107,294
Total assets	1,747,753	1,642,075
Current liabilities:
Accounts payable	44,045	33,829
Accrued expenses	107,328	134,095
Deferred revenue	3,303	3,303
Other current liabilities	7,413	2,463
Total current liabilities	162,089	173,690
Long-term debt	431,040	420,554
Lease liabilities	50,209
Deferred rent and other	5,248	15,555
Total liabilities	648,586	609,799
Commitments and contingencies (Note 14)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 3,333,333 shares authorized; none issued and outstanding
Common stock, $0.0001 par value, 99,000,000 shares authorized; 74,327,767 and 71,071,887 issued and outstanding at June 30, 2019, and December 31, 2018, respectively	7	7
Additional paid-in capital	3,031,050	2,611,294
Accumulated other comprehensive income (loss)	82	(99)
Accumulated deficit	(1,931,972)	(1,578,926)
Total stockholders’ equity	1,099,167	1,032,276
Total liabilities and stockholders’ equity	$ 1,747,753	$ 1,642,075