Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 63,961	$ 146,205
Restricted cash	4,012
Accounts receivable	22,650	16,095
Inventory	32,752	24,736
Prepaid expenses and other current assets	7,855	5,710
Total current assets	131,230	192,746
Restricted cash	43,823	500
Property, plant, and equipment	7,255	5,312
Leased property under capital lease	1,667	1,937
Note receivable	383	447
Goodwill	8,478
Intangible assets, net	4,644	1,490
Other assets	11,976	1,719
Total assets	209,456	204,151
Current liabilities:
Accounts payable	20,455	10,185
Accrued expenses	9,852	8,750
Product warranty reserve	406	1,311
Accrual for loss contracts related to service	4,100
Deferred revenue	4,468	3,319
Obligations under capital lease		587
Other current liabilities	3,425	1,555
Total current liabilities	42,706	25,707
Accrual for loss contracts related to service	5,950
Deferred revenue	13,997	6,772
Common stock warrant liability	5,735	9,418
Finance obligations	14,809	2,426
Other liabilities	370	392
Total liabilities	83,567	44,715
Redeemable preferred stock
Series C redeemable convertible preferred stock, $0.01 par value per share (aggregate involuntary liquidation preference $16,664) 10,431 shares authorized; Issued and outstanding: 5,231 at December 31, 2015 and December 31, 2014	1,153	1,153
Stockholders' equity:
Common stock, $0.01 par value per share; 450,000,000 shares authorized; Issued (including shares in treasury): 180,567,444 at December 31, 2015 and 173,644,532 at December 31, 2014	1,806	1,736
Additional paid-in capital	1,118,917	1,096,392
Accumulated other comprehensive income	798	898
Accumulated deficit	(993,876)	(938,081)
Less common stock in treasury: 479,953 at December 31, 2015 and 378,116 at December 31, 2014	(2,909)	(2,662)
Total stockholders' equity	124,736	158,283
Total liabilities, redeemable preferred stock, and stockholders' equity	$ 209,456	$ 204,151