Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 39,206	$ 48,921
Marketable securities	235,464	262,179
Accounts receivable, net	16,214	8,526
Inventory, net	7,859	6,833
Prepaid expenses and other current assets	7,443	7,114
Total current assets	306,186	333,573
Property and Equipment, at cost:
Computer equipment and computer software	22,485	20,767
Laboratory equipment	15,837	14,749
Leasehold improvements	13,653	13,549
Assets under construction	7,200	6,711
Buildings	4,792	4,792
Furniture and fixtures	2,581	2,515
Property and Equipment, gross	66,548	63,083
Less-Accumulated depreciation	(28,153)	(24,941)
Net property and equipment	38,395	38,142
Other long-term assets	5,680	5,325
Total assets	350,261	377,040
Current Liabilities:
Accounts payable	891	710
Accrued liabilities	27,077	28,106
Current portion of long-term debt	176	174
Other short-term liabilities	1,793	1,702
Total current liabilities	29,937	30,692
Long-term debt	4,592	4,633
Other long-term liabilities	5,680	5,734
Lease incentive obligation, less current portion	532	686
Total liabilities	40,741	41,745
Commitments and contingencies
Stockholders' Equity:
Preferred stock, $0.01 par value Authorized—5,000,000 shares issued and outstanding—no shares at March 31, 2017 and December 31, 2016
Common stock, $0.01 par value Authorized—200,000,000 shares issued and outstanding—111,197,740 and 110,236,127 shares at March 31, 2017 and December 31, 2016	1,112	1,102
Additional paid-in capital	1,090,002	1,080,432
Accumulated other comprehensive loss	(431)	(418)
Accumulated deficit	(781,163)	(745,821)
Total stockholders' equity	309,520	335,295
Total liabilities and stockholders’ equity	$ 350,261	$ 377,040