Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (28,873,000)	$ (13,480,000)
Adjustments to reconcile net loss to cash used in operating activities:
Initial loss on common stock warrant and common stock adjustment feature liabilities		4,000,000
Change in fair value of common stock warrant and common stock adjustment feature liabilities	9,243,000	(9,561,000)
Change in fair value of contingent consideration	(1,000,000)
Offering costs	708,000	2,555,000
Depreciation	194,000	154,000
Lease amortization	708,000
Loss (gain) on disposal of equipment	3,000	(3,000)
Net amortization of investment premium	(180,000)	(193,000)
Stock-based compensation	2,287,000	1,550,000
Write down of inventory	304,000	310,000
Changes in operating assets and liabilities:
Accounts receivable	(437,000)	1,066,000
Unbilled revenue	3,000	2,000
Inventories	(1,535,000)	160,000
Prepaid expenses and other current assets	(8,000)	(151,000)
Other noncurrent assets	(1,000)
Accounts payable and accrued expenses	2,102,000	176,000
Amounts due to related parties	11,000	(1,000)
Unearned revenue	(54,000)	(312,000)
Other current liabilities	42,000	25,000
Other noncurrent liabilities		72,000
Operating lease payments	(715,000)
Net cash used in operating activities	(17,198,000)	(13,631,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sale of property and equipment	16,000	10,000
Purchases of property and equipment	(1,477,000)	(250,000)
Purchases of investments	(28,358,000)	(29,885,000)
Proceeds from sales and maturities of investments	21,450,000	24,150,000
Net cash used in investing activities	(8,369,000)	(5,975,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on notes payable	(8,000)
Proceeds from exercise of warrants	5,269,000
Proceeds from exercise of stock options and purchases through ESPP	21,000	969,000
Capital contributions received from non-controlling interest	689,000
Net cash provided by financing activities	21,986,000	22,479,000
Net (decrease) increase in cash and cash equivalents	(3,581,000)	2,873,000
Cash and cash equivalents — beginning of period	11,998,000	9,125,000
Cash and cash equivalents — end of period	8,417,000	11,998,000
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	4,000
Cash paid for taxes	2,000	34,000
NONCASH TRANSACTIONS:
Offering costs in accounts payable and accrued expenses at end of period	20,000	23,000
Reclassification of common stock warrant liability balance with warrant exercises	7,016,000
Reclassification of unearned revenue to other short term liabilities		259,000
Reclassification of common stock adjustment feature liability balance to equity		8,378,000
Right of use assets obtained in exchange for new operating lease liabilities	2,328,000
Right of use assets obtained through modification of existing lease agreement	194,000
Fixed assets acquired with notes payable	139,000
Purchases of fixed assets included in accounts payable and accrued expenses	1,000
March 2018 Purchase Agreement [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock and warrants from purchase agreement		10,000,000
Payments of offering costs relating to purchase agreement		(1,308,000)
NONCASH TRANSACTIONS:
Common stock warrants issued to placement agent and included in offering costs related to purchase agreement		526,000
June 2019 Offering [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock and warrants from Offering	7,500,000
Payments of offering costs	(663,000)
NONCASH TRANSACTIONS:
Common stock warrants issued to placement agent and included in offering costs	86,000
September 2019 Offering [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock and warrants from Offering	10,000,000
Payments of offering costs	(798,000)
NONCASH TRANSACTIONS:
Common stock warrants issued to placement agent and included in offering costs	95,000
June 2018 Offering [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock and warrants from Offering		14,000,000
Payments of offering costs	$ (24,000)	(1,182,000)
NONCASH TRANSACTIONS:
Common stock warrants issued to placement agent and included in offering costs		$ 239,000