Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 13,825	$ 24,828
Restricted cash	15,803	13,898
Accounts receivable	24,721	15,331
Inventory	53,428	48,776
Prepaid expenses and other current assets	16,050	16,774
Total current assets	123,827	119,607
Restricted cash	32,424	29,329
Property, plant, and equipment, net of accumulated depreciation of $33,401 and $31,588, respectively	13,155	10,414
Leased property, net of accumulated depreciation of $8,826 and $11,812, respectively	130,015	87,065
Goodwill	9,157	9,445
Intangible assets, net of accumulated amortization of $2,203 and $1,735, respectively	4,058	3,785
Other assets	6,642	11,165
Total assets	319,278	270,810
Current liabilities:
Accounts payable	37,105	42,362
Accrued expenses	8,553	10,595
Deferred revenue	10,996	8,630
Finance obligations	48,705	34,506
Current portion of long-term debt	11,489	18,762
Other current liabilities	247	866
Total current liabilities	117,095	115,721
Deferred revenue	28,525	25,809
Common stock warrant liability	1,083	4,391
Finance obligations	86,562	37,069
Convertible senior notes, net	61,509
Long-term debt	9,372	13,371
Other liabilities	18	94
Total liabilities	304,164	196,455
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: 2,620 at September 30, 2018 and December 31, 2017	709	709
Stockholders' equity:
Common stock, $0.01 par value per share; 750,000,000 shares authorized; Issued (including shares in treasury): 232,511,393 at September 30, 2018 and 229,073,517 at December 31, 2017	2,326	2,291
Additional paid-in capital	1,284,384	1,250,899
Accumulated other comprehensive income	1,762	2,194
Accumulated deficit	(1,243,430)	(1,178,636)
Less common stock in treasury: 15,002,663 at September 30, 2018 and 587,151 at December 31, 2017	(30,637)	(3,102)
Total stockholders' equity	14,405	73,646
Total liabilities, redeemable preferred stock, and stockholders' equity	$ 319,278	$ 270,810