Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 148,695	$ 77,491
Marketable securities	893,474	347,224
Accounts receivable, net	34,575	26,419
Inventory, net	32,380	26,027
Prepaid expenses and other current assets	12,867	10,055
Total current assets	1,121,991	487,216
Long-term Assets:
Property, plant and equipment, net	103,448	79,986
Intangibles, net	21,558	22,160
Other long-term assets, net	9,919	9,198
Total assets	1,256,916	598,560
Current Liabilities:
Accounts payable	12,274	16,135
Accrued liabilities	56,716	49,126
Accrued interest	1,407
Debt, current portion	183	182
Other short-term liabilities	2,750	2,681
Total current liabilities	73,330	68,124
Convertible notes, net	486,688
Long-term debt	4,237	4,269
Other long-term liabilities	5,643	5,749
Total liabilities	569,898	78,142
Commitments and contingencies
Stockholders' Equity:
Preferred stock, $0.01 par value Authorized—5,000,000 shares issued and outstanding—no shares at March 31, 2018 and December 31, 2017
Common stock, $0.01 par value Authorized—200,000,000 shares issued and outstanding—121,866,759 and 120,497,426 shares at March 31, 2018 and December 31, 2017	1,219	1,205
Additional paid-in capital	1,588,173	1,380,577
Accumulated other comprehensive loss	(2,336)	(750)
Accumulated deficit	(900,038)	(860,614)
Total stockholders' equity	687,018	520,418
Total liabilities and stockholders’ equity	$ 1,256,916	$ 598,560