Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 410,375	$ 599,691
Short-term investments	538,769	479,369
Accounts receivable	42,985	29,468
Inventory	104,126	83,605
Other current assets	42,989	36,511
Total current assets	1,139,244	1,228,644
Property and equipment, net of accumulated depreciation of $22,124 and $18,022 as of June 30, 2018 and December 31, 2017, respectively	57,624	43,156
Intangible assets, net of accumulated amortization of $5,100 and $4,145 as of June 30, 2018 and December 31, 2017, respectively	14,857	14,355
Other assets	35,435	21,809
Total assets	1,247,160	1,307,964
Current liabilities:
Accounts payable	17,382	8,467
Accrued expenses	72,477	68,982
Current portion of long-term debt	9,514	6,175
Deferred revenue	3,303	3,316
Other current liabilities	2,011	1,392
Total current liabilities	104,687	88,332
Long-term debt	429,925	424,876
Deferred rent and other	13,501	5,539
Total liabilities	548,113	518,747
Commitments and contingencies (Note 16)
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; 66,346,248 and 64,791,670 issued and outstanding at June 30, 2018 and December 31, 2017, respectively	7	6
Additional paid-in capital	2,061,039	2,006,598
Accumulated other comprehensive loss	(361)	(379)
Accumulated deficit	(1,361,638)	(1,217,008)
Total stockholders’ equity	699,047	789,217
Total liabilities and stockholders’ equity	$ 1,247,160	$ 1,307,964