Basis of Presentation - Narrative (Details)							3 Months Ended		6 Months Ended
	Jun. 10, 2020 USD ($) shares	May 26, 2020 $ / shares shares	Sep. 10, 2019 USD ($) $ / shares shares	Sep. 09, 2019 USD ($)	Jun. 04, 2019	May 01, 2019	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Apr. 30, 2020 $ / shares	Apr. 01, 2020	Dec. 31, 2019 USD ($) $ / shares shares	May 31, 2019 shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reduction in executive salaries												20.00%
Reduction in salaried employee salaries												20.00%
Reduction of working hours for hourly employees												20.00%
Workforce brought back							20.00%		20.00%
Reverse stock split					0.1
Common stock shares authorized after reversed stock split (in shares) | shares							30,000,000		30,000,000				30,000,000	30,000,000
Series A Cumulative Perpetual Preferred Stock, dividend rate			0.100						0.100
Series A Cumulative Perpetual Preferred Stock, par value (USD per share)			$ 0.0001
Preferred stock, dividend rate percentage									10.00%
Preferred stock, par value (in usd per share) | $ / shares							$ 0.0001		$ 0.0001
Preferred stock, liquidation preference per share (USD per share) | $ / shares							10.00		10.00
Common stock, par value (in usd per share) | $ / shares							0.0001		0.0001				$ 0.0001
Exercise price of warrants (usd per share) | $ / shares							$ 2.25		$ 2.25
Net proceeds from sale of common stock and warrants									$ 4,203,000	$ 0
Gross proceeds from private placement				$ 3,000,000.0
(Loss) income from operations by segment							$ (1,526,000)	$ (1,146,000)	(4,130,000)	(2,281,000)
Accumulated deficit							(122,769,000)		(122,769,000)				$ (118,529,000)
Net cash provided by (used in) operating activities									49,000	$ 368,000
Short-term debt and current portion of long-term debt							4,459,000		4,459,000				4,036,000
Payable to related parties							2,155,000		2,155,000				1,920,000
Derivative liability													$ 10,000
Capitalized implementation costs									600,000
Equity Offering
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock, par value (in usd per share) | $ / shares											$ 0.0001
Number of shares issued in transaction | shares	2,450,000	2,225,000
Number of securities called by warrants | shares		1,112,500
Price of stock sold (in dollars per share) | $ / shares		$ 2.25
Net proceeds from sale of common stock and warrants									4,200,000
Gross proceeds from private placement	$ 5,500,000
Proceeds from issuance of common stock to fund modular housing project									3,000,000.0
Equity Offering | Common stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Price of stock sold (in dollars per share) | $ / shares		$ 2.24
Equity Offering | Stock warrants
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of warrants issued in transaction | shares		2,225,000
Price of stock sold (in dollars per share) | $ / shares		$ 0.01
Over-Allotment Option
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of securities called by warrants | shares		225,000
Price of stock sold (in dollars per share) | $ / shares		$ 2.24
Exercise price of warrants (usd per share) | $ / shares		$ 0.01
Over-Allotment Option | Stock warrants
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of warrants issued in transaction | shares		225,000
Number of securities called by warrants | shares		112,500
Healthcare
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in revenue							(8,500,000)		(9,100,000)
Building and Construction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in revenue							5,000,000.0		10,500,000
ATRM Holdings, Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Shares issued in business acquisition (In shares) | shares			1,615,637
Series A Preferred Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Digirad shares issued per ATRM share (in shares)				0.03
Series A Preferred Stock | Put Option
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Derivative liability							$ 1,000,000.0		$ 1,000,000.0
Series A Preferred Stock | ATRM Holdings, Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Digirad shares issued per ATRM share (in shares)			0.03
Shares issued in business acquisition (In shares) | shares			1,615,637
Series B Preferred Stock | ATRM Holdings, Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Digirad shares issued per ATRM share (in shares)			2.5	2.5
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reverse stock split						0.2
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reverse stock split						0.1
ATRM Holdings, Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Preferred stock, dividend rate percentage			10.00%
Preferred stock, par value (in usd per share) | $ / shares			$ 0.001