Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($)	Dec. 31, 2017	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 15,117,544	$ 12,803,887
Short-term marketable securities	3,602,254	4,359,542
Accounts receivable, net	5,678,220	5,681,882
Inventories, net	5,259,934	5,257,234
Prepaid expenses and other	589,561	983,322
Total current assets	30,247,513	29,085,867
Long-term marketable securities	1,005,660	711,124
Deferred tax assets, net	5,622,112	8,331,000
Property and equipment, net	505,469	509,603
Intangible assets, net	53,885	55,689
Other assets	117,644	164,517
Total assets	37,552,283	38,857,800
Current liabilities:
Accounts payable	1,903,001	1,112,366
Accrued liabilities	1,858,548	2,561,395
Total liabilities	3,761,549	3,673,761
Commitments and contingencies (Note 9)
Stockholders' equity:
Preferred stock, $0.00001 par value; 5,000,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.00001 par value; 50,000,000 shares authorized; 32,249,288 and 32,158,436 shares issued and outstanding, respectively	322	322
Additional paid-in capital	88,254,818	87,956,839
Accumulated deficit	(54,455,106)	(52,771,853)
Accumulated other comprehensive loss	(9,300)	(1,269)
Total stockholders' equity	33,790,734	35,184,039
Total liabilities and stockholders' equity	$ 37,552,283	$ 38,857,800

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).

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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.