Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 498,980	$ 643,095
Accounts receivable	44,182	53,416
Inventories	74,444	57,939
Other current assets	38,184	33,511
Total current assets	655,790	787,961
Intangible assets, net	54,947	56,384
Property and equipment, net	10,272	9,652
Restricted cash	2,556	2,552
Other assets	6,127	5,636
Total assets	729,692	862,185
Current liabilities:
Accounts payable	5,079	4,172
Accrued expenses	150,589	154,808
Deferred revenue, current	117	324
Other current liabilities	7,451	6,902
Total current liabilities	163,236	166,206
Convertible notes, net	146,529	143,446
Long-term debt, net	293,888	293,659
Deferred revenue, non-current	188	211
Other non-current liabilities	8,123	9,577
Total liabilities	611,964	613,099
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized at both December 31, 2017 and March 31, 2018; no shares issued or outstanding at both December 31, 2017 and March 31, 2018
Common stock, $0.0001 par value; 100,000,000 shares authorized at both December 31, 2017 and March 31, 2018; 54,464,039 and 54,801,636 shares issued and outstanding at December 31, 2017 and March 31, 2018, respectively	5	5
Additional paid-in capital	1,755,783	1,724,850
Accumulated other comprehensive loss	(5,357)	(5,882)
Accumulated deficit	(1,632,703)	(1,469,887)
Total stockholders' equity	117,728	249,086
Total liabilities and stockholders' equity	$ 729,692	$ 862,185