Consolidated Statements of Cash Flows - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Cash flows from operating activities:    
Net loss $ (21,915,000) $ (42,526,000)
Adjustments to reconcile net loss to net cash used in operating activities:    
Provision for doubtful accounts 454,000 1,028,000
Depreciation and amortization 1,295,000 1,177,000
Stock-based compensation 2,651,000 2,400,000
Non-cash interest expense 535,000 1,577,000
Amortization of operating lease right-of-use assets and accretion of operating lease liabilities 2,000 5,000
Loss on debt restructuring 6,705,000
Loss from minority interest in limited liability company 383,000 627,000
Loss on disposal of property and equipment 20,000 108,000
Modification of Series A and B warrants 1,838,000
Changes in assets and liabilities:    
Accounts receivable 349,000 3,103,000
Inventory 1,360,000 (1,070,000)
Prepaid expenses and other current assets 151,000 111,000
Other noncurrent assets 461,000 40,000
Accounts payable (727,000) (2,386,000)
Accrued and other liabilities (2,422,000) (1,536,000)
Other noncurrent liabilities 331,000 (599,000)
Net cash used in operating activities (15,234,000) (31,236,000)
Cash flows from investing activities:    
Purchase of property and equipment (781,000) (1,087,000)
Net cash used in investing activities (781,000) (1,087,000)
Cash flows from financing activities:    
Proceeds from exercise of common warrants 8,407,000
Transaction costs in connection with 2020 Warrant Offering (334,000)
Proceeds from Paycheck Protection Program loan 1,343,000
Proceeds from intial purchase of common shares under Purchase Agreement with LPC 341,000
Proceeds from sale of common shares, net of issuance cost 16,274,000
Proceeds from issuance of common shares from employee stock purchase plan 56,000
Transaction costs in connection with note payable (216,000)
Reverse stock split - cancellation and payout of fractional shares (6,000)
Net cash provided by financing activities 9,230,000 16,108,000
Net decrease in cash and cash equivalents (6,785,000) (16,215,000)
Cash and cash equivalents - beginning of period 13,308,000 29,523,000
Cash and cash equivalents - end of period 6,523,000 13,308,000
Supplemental disclosure:    
Cash paid for interest 2,508,000
Cash paid for income taxes
Supplemental disclosure of cash flow information as of end of period:    
Issuance of Series B convertible preferred stock in settlement of dividends 4,141,000 378,000
Issuance of note payable in settlement of accrued interest 532,000 1,226,000
Net transfer of equipment between inventory and property and equipment 247,000 207,000
Issuance of Series B convertible preferred stock and common stock warrants in connection with debt conversion 35,529,000
Operating cash outflows from operating leases 303,000 295,000
Right-of-use assets obtained in exchange for operating lease liabilities (upon adoption of ASC 842) 629,000
November 2019 Offering [Member]    
Cash flows from financing activities:    
Transaction costs in connection with November 2019 Offering (33,000)
Purchase Agreement with LPC [Member]    
Cash flows from financing activities:    
Transaction costs in connection with November 2019 Offering $ (494,000)