Consolidated Balance Sheets - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Current assets:    
Cash and cash equivalents $ 38,602 $ 24,828
Restricted cash 17,399 13,898
Accounts receivable 37,347 24,179
Inventory 47,910 48,776
Prepaid expenses and other current assets 14,357 7,926
Total current assets 155,615 119,607
Restricted cash 54,152 29,329
Property, plant, and equipment, net 12,869 10,414
Leased property, net 146,751 87,065
Goodwill 9,023 9,445
Intangible assets, net 3,890 3,785
Other assets 8,026 11,165
Total assets 390,326 270,810
Current liabilities:    
Accounts payable 34,824 42,362
Accrued expenses 7,864 10,595
Deferred revenue 12,055 8,630
Finance obligations 74,264 34,506
Current portion of long-term debt 16,803 18,762
Other current liabilities 560 866
Total current liabilities 146,370 115,721
Deferred revenue 28,021 25,809
Common stock warrant liability 105 4,391
Finance obligations 118,076 37,069
Convertible senior notes, net 63,247  
Long-term debt 133 13,371
Other liabilities 18 94
Total liabilities 355,970 196,455
Stockholders' equity:    
Common stock, $0.01 par value per share; 750,000,000 shares authorized; Issued (including shares in treasury): 234,160,661 at December 31, 2018 and 229,073,517 at December 31, 2017 2,342 2,291
Additional paid-in capital 1,289,714 1,250,899
Accumulated other comprehensive income 1,584 2,194
Accumulated deficit (1,260,290) (1,178,636)
Less common stock in treasury: 15,002,663 at December 31, 2018 and 587,151 at December 31, 2017 (30,637) (3,102)
Total stockholders' equity 2,713 73,646
Total liabilities, redeemable preferred stock, and stockholders' equity 390,326 270,810
Series C Redeemable Convertible Preferred Stock    
Redeemable preferred stock:    
Redeemable preferred stock 709 $ 709
Series E Redeemable Convertible Preferred Stock    
Redeemable preferred stock:    
Redeemable preferred stock $ 30,934