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Initial commitment fee.

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Percentage issuance of common stock.

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Stockholders' Equity - Common stock (Details) - USD ($)						1 Months Ended			3 Months Ended						9 Months Ended			12 Months Ended
Stockholders' Equity - Common stock (Details) - USD ($)	Sep. 09, 2022	Aug. 02, 2022	May 16, 2022	Jan. 14, 2022	Jun. 16, 2020	Oct. 20, 2022	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Aug. 17, 2022	Aug. 15, 2022	Jul. 14, 2022	Oct. 23, 2020
Class of Stock [Line Items]
Sale of common stock, net									$ 6,815,000	$ 152,000	$ 7,742,000	$ 6,354,000	$ 5,094,000	$ 7,078,000
Common stock, shares authorized (in shares)							100,000,000	100,000,000	100,000,000						100,000,000			100,000,000
Proceeds from sale of common stock, net															$ 14,558,000	$ 18,665,000
Common Stock [Member]
Class of Stock [Line Items]
Sale of common stock, net									$ 10,000		$ 6,000	$ 3,000	$ 2,000	$ 2,000
Common stock issued (in shares)									10,101,320	271,047	6,687,610	3,272,500	1,907,000	2,534,879
Number of stock repurchased															0
Common Stock [Member] \| Maximum [Member]
Class of Stock [Line Items]
Authorized amount of repurchase of stock																				$ 2,000,000.0
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Maximum [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			57,500,000
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Maximum value of shares to be issued under agreement		$ 50,000,000.0
Common stock issued (in shares)								4,000,000
Period exercisable from the date of issuance															36 months
Number of maximum common shares can be resale																			9,500,000
Initial commitment shares		492,698																			492,698
Initial commitment fee paid in cash		$ 125,000
Aggregate gross proceeds from sales of common stock		$ 25,000,000.0
Proceeds from sale of common stock, net								$ 3,200,000
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member] \| Subsequent Event [Member]
Class of Stock [Line Items]
Common stock issued (in shares)						0
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member] \| Minimum [Member]
Class of Stock [Line Items]
Percentage issuance of common stock			19.99%
2022 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member] \| Maximum [Member]
Class of Stock [Line Items]
Number of shares reserved for issuance and sale																			9,007,302
2020 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Maximum value of shares to be issued under agreement																	$ 25,000,000.0
Common stock issued (in shares)															5,665,000			5,685,186
Period exercisable from the date of issuance																	36 months
Proceeds from sale of common stock, net															$ 7,000,000.0			$ 12,500,000
Remaining common stock issued and sold (in shares)							0	0	0						0
2020 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member] \| Minimum [Member]
Class of Stock [Line Items]
Percentage issuance of common stock					19.99%
2020 Purchase Agreement [Member] \| Lincoln Park Capital Fund, LLC [Member] \| Common Stock [Member] \| Maximum [Member]
Class of Stock [Line Items]
Common stock issued (in shares)					23,800,000
Sales Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member] \| At The Market Offering Program [Member]
Class of Stock [Line Items]
Remaining availability under financing facility																						$ 0
September 2022 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| At The Market Offering Program [Member]
Class of Stock [Line Items]
Reimburse of fee and disbursements expenses	$ 50,000
September 2022 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member] \| At The Market Offering Program [Member]
Class of Stock [Line Items]
Common stock issued (in shares)							0
September 2022 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member] \| At The Market Offering Program [Member] \| Subsequent Event [Member]
Class of Stock [Line Items]
Common stock issued (in shares)						1,000,000
Proceeds from sale of common stock, net						$ 600,000
September 2022 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member] \| Maximum [Member] \| At The Market Offering Program [Member]
Class of Stock [Line Items]
Proceeds from sale of common stock, net	$ 5,000,000
Percentage of commission on gross proceeds from sale of common stock	3.00%
January 2022 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Common stock issued (in shares)															6,902,279
Proceeds from sale of common stock, net															$ 4,500,000
January 2022 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member] \| At The Market Offering Program [Member]
Class of Stock [Line Items]
Remaining availability under financing facility				$ 0
January 2022 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member] \| Maximum [Member] \| At The Market Offering Program [Member]
Class of Stock [Line Items]
Proceeds from sale of common stock, net				$ 5,000,000
2020 Distribution Agreement [Member] \| Canaccord Genuity LLC [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Common stock issued (in shares)																		2,179,193
Proceeds from sale of common stock, net																		$ 6,300,000