CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 4,765	$ 7,104
Short-term investments	1,564
Accounts receivable	2,171	1,622
Inventories	902	1,148
Prepaid expenses and other	1,171	923
Total current assets	10,573	10,797
Property and equipment, net	255	279
Goodwill	420	420
Right-of-use lease asset	297
Other	260	260
Total assets	11,805	11,756
Current liabilities
Accounts payable	215	236
Deferred revenue	269	273
Short-term lease liability	197
Accrued expenses and other	1,098	1,402
Total current liabilities	1,779	1,911
Long-term lease liability	115	17
Convertible notes payable	2,749	2,671
Total liabilities	4,643	4,599
Commitments and contingencies (Note 4)
Stockholders' equity
Preferred stock, $0.01 par value; 20,000 shares authorized; none issued and Outstanding
Common stock, $0.001 par value; 120,000 shares authorized; 43,139 shares and 42,967 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively	43	43
Additional paid-incapital	242,976	242,981
Accumulated deficit	(235,857)	(235,867)
Total stockholders' equity	7,162	7,157
Total liabilities and stockholders' equity	$ 11,805	$ 11,756

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682