Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 63,509	$ 46,966
Marketable securities available-for-sale	522	51,009
Accounts receivable, net	284	2,647
Inventories	2,345	3,212
Current assets of discontinued operations	0	13,389
Prepaid expenses and other current assets	1,339	1,721
Total current assets	67,999	118,944
Property, plant and equipment, net	22,674	25,996
Equity method investments	43,856	35,910
Noncurrent assets of discontinued operations	0	348
Other assets	1,180	774
Total assets	135,709	181,972
Current liabilities:
Accounts payable	4,159	4,951
Accrued liabilities	8,856	13,306
Deferred revenue	3,272	4,159
Current liabilities of discontinued operations	0	2,914
Total current liabilities	16,287	25,330
Deferred revenue	0	500
Convertible debt	174,620	202,015
Noncurrent liabilities of discontinued operations	0	26
Other liabilities	1,395	576
Total liabilities	192,302	228,447
Commitments and contingencies (Note 11)
Stockholders’ deficit:
Convertible preferred stock, par value $0.001—5,000 shares authorized; 27 and zero shares issued and outstanding at December 31, 2016 and 2015, respectively	25,653	0
Common stock, par value $0.001—225,000 shares authorized; 96,436 and 81,734 shares issued and outstanding at December 31, 2016 and 2015, respectively	96	82
Additional paid-in capital	645,927	585,679
Accumulated other comprehensive loss	(16,808)	(22,331)
Accumulated deficit	(711,461)	(609,905)
Total stockholders’ deficit	(82,246)	(46,475)
Total liabilities, convertible preferred stock and stockholders’ deficit	$ 135,709	$ 181,972