Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 46,014	$ 63,961
Restricted cash	11,219	4,012
Accounts receivable	11,923	22,650
Inventory	29,940	32,752
Prepaid expenses and other current assets	11,837	7,855
Total current assets	110,933	131,230
Restricted cash	43,403	43,823
Property, plant, and equipment, net of accumulated depreciation of $29,204 and $27,970, respectively	8,246	7,255
Leased property, net	54,060	1,667
Goodwill	8,291	8,478
Intangible assets, net	3,933	4,644
Other assets	11,966	12,359
Total assets	240,832	209,456
Current liabilities:
Accounts payable	32,112	20,455
Accrued expenses	8,519	9,852
Accrual for loss contracts related to service	752	4,100
Deferred revenue	5,736	4,468
Finance obligations	14,787	2,671
Current portion of long-term debt	2,964
Other current liabilities	1,615	1,160
Total current liabilities	66,485	42,706
Accrual for loss contracts related to service		5,950
Deferred revenue	17,413	13,997
Common stock warrant liability	11,387	5,735
Finance obligations	29,767	14,809
Long-term debt	20,829
Other liabilities	241	370
Total liabilities	146,122	83,567
Stockholders' equity:
Common stock, $0.01 par value per share; 450,000,000 shares authorized; Issued (including shares in treasury): 181,009,135 at September 30, 2016 and 180,567,444 at December 31, 2015	1,917	1,806
Additional paid-in capital	1,137,482	1,118,917
Accumulated other comprehensive income	247	798
Accumulated deficit	(1,051,467)	(993,876)
Less common stock in treasury: 582,328 at December 31, 2016 and 479,953 December 31, 2015	(3,091)	(2,909)
Total stockholders' equity	85,088	124,736
Total liabilities, redeemable preferred stock, and stockholders' equity	240,832	209,456
Series C Redeemable Convertible Preferred Stock
Redeemable preferred stock
Redeemable preferred stock	1,153	$ 1,153
Series D Redeemable Convertible Preferred Stock
Redeemable preferred stock
Redeemable preferred stock	$ 8,469