Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income	$ 189	$ 6,953
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	2,037	1,989
Stock-based compensation expense	2,232	1,825
Provision adjustments related to credit loss	165	(52)
Provision adjustments related to product warranty	139	222
(Gain) loss on disposal of property, plant, and equipment	(601)	189
Other	464	(292)
Total non-cash adjustments	4,436	3,881
Changes in operating assets and liabilities:
Accounts receivable and contract assets	4,351	(3,574)
Inventory	6,663	(3,909)
Other assets	(4,857)	1,121
Accounts payable	(4,893)	(660)
Accrued expenses and other current liabilities	5,646	(2,040)
Total change in operating assets and liabilities	6,910	(9,062)
Net cash provided by operating activities	11,535	1,772
Cash flows from investing activities:
Purchase of equipment	(3,297)	(1,142)
Proceeds from disposal of property, plant, and equipment	1,128	583
Net cash used in investing activities	(2,169)	(559)
Cash flows from financing activities:
Proceeds from employee stock purchase plan and equity awards	29	428
Proceeds from sale of common stock	0	35,937
Issuance cost associated with sale of common stock	0	(2,796)
Taxes paid related to net share settlement of equity awards	(156)	(83)
Net cash (used in) provided by financing activities	(127)	33,486
Effect of exchange rate changes provided by foreign currency	28	44
Net increase in cash, cash equivalents, and restricted cash	9,267	34,743
Cash, cash equivalents, and restricted cash at beginning of period	71,682	30,538
Cash, cash equivalents, and restricted cash at end of period	80,949	65,281
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	30	31
Cash paid during the period for income taxes	361	295
NON-CASH INVESTING AND FINANCING ACTIVITIES
Changes in accounts payable related to purchases of equipment	$ (11)	$ (256)

Increase (Decrease) in Accounts Payable Related to Property and Equipment Purchases

No definition available.

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Namespace Prefix:	emkr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate amount of adjustments to net income or loss necessary to remove the effects of all items whose cash effects are investing or financing cash flows. The aggregate amount also includes all noncash expenses and income items which reduce or increase net income and are thus added back or deducted when calculating cash provided by or used in operating activities.