Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 60,027	$ 46,966
Marketable securities available-for-sale	27,771	51,009
Accounts receivable, net	1,150	2,647
Inventories	3,915	3,212
Current assets of discontinued operations	0	13,389
Prepaid expenses and other current assets	1,566	1,721
Total current assets	94,429	118,944
Property, plant and equipment, net	23,962	25,996
Equity method investments	37,559	35,910
Noncurrent assets of discontinued operations	0	348
Other assets	1,151	774
Total assets	157,101	181,972
Current liabilities:
Accounts payable	4,516	4,951
Accrued liabilities	11,994	13,306
Deferred revenue	5,945	4,159
Current liabilities of discontinued operations	0	2,914
Total current liabilities	22,455	25,330
Deferred revenue	0	500
Convertible debt	191,651	202,015
Noncurrent liabilities of discontinued operations	0	26
Other liabilities	1,254	576
Total liabilities	215,360	228,447
Commitments and contingencies
Convertible preferred stock, par value $0.001—5,000,000 shares authorized; 26,850 and zero shares issued and outstanding at September 30, 2016 and December 31, 2015, respectively	25,749	0
Common stock, par value $0.001—225,000,000 and 150,000,000 shares authorized at September 30, 2016 and December 31, 2015, respectively; 88,110,857 and 81,734,078 shares issued and outstanding at September 30, 2016 and December 31, 2015, respectively	88	82
Additional paid-in capital	616,099	585,679
Accumulated other comprehensive loss	(15,846)	(22,331)
Accumulated deficit	(684,349)	(609,905)
Total stockholders’ deficit	(84,008)	(46,475)
Total liabilities, convertible preferred stock and stockholders’ deficit	$ 157,101	$ 181,972