Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (10,029,000)	$ (12,669,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Provision for doubtful accounts	111,000	42,000
Depreciation and amortization	311,000	150,000
Stock-based compensation	496,000	753,000
Non-cash interest expense	399,000	386,000
Amortization of operating lease right-of-use assets and accretion of operating lease liabilities	10,000
Loss from minority interest in limited liability company	125,000	249,000
Changes in assets and liabilities:
Accounts receivable	815,000	(828,000)
Inventory	206,000	(1,497,000)
Prepaid expenses and other current assets	(559,000)	(561,000)
Other noncurrent assets	17,000	(2,000)
Accounts payable	(1,310,000)	(934,000)
Accrued and other liabilities	(2,202,000)	(366,000)
Other noncurrent liabilities	52,000	86,000
Net cash used in operating activities	(11,558,000)	(15,191,000)
Cash flows from investing activities:
Purchase of property and equipment	(179,000)	(462,000)
Net cash used in investing activities	(179,000)	(462,000)
Cash flows from financing activities:
Proceeds from sale of common stock, net of issuance costs		33,236,000
Proceeds from issuance of common shares from employee stock purchase plan	35,000	65,000
Net cash provided by financing activities	35,000	33,301,000
Net increase (decrease) in cash and cash equivalents	(11,702,000)	17,648,000
Cash and cash equivalents - beginning of period	29,523,000	20,730,000
Cash and cash equivalents - end of period	17,821,000	38,378,000
Supplemental disclosure:
Cash paid for interest	675,000	653,000
Cash paid for income taxes
Supplemental disclosure of cash flow information as of end of period:
Issuance of note payable in settlement of accrued interest	318,000	305,000
Net transfer of equipment between inventory and property and equipment	46,000	59,000
Operating cash outflows from operating leases	73,000
Right-of-use assets obtained in exchange for operating lease liabilities (upon adoption of ASC 842)	$ 629,000