Capital Stock and Share-Based Compensation - Equity Transactions (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Stockholders' Equity
Stockholder's equity beginning balance	$ 69,801	$ 67,777	$ 67,469	$ 65,189	$ 64,008	$ 62,354	$ 67,469	$ 62,354
Exercise of stock options (in shares)							688,495
Exercise of stock options	34	726	1,198	71	182	185
Share-based compensation	571	465	502	420	378	343
Deferred compensation issuance		78
Net income	3,102	1,369	(1,116)	1,230	841	1,126	$ 3,355	3,196
Forfeitures of restricted stock	125	(410)	(276)
Purchase of treasury stock	(125)	(204)		(2,000)	(220)
Stockholder's equity ending balance	$ 73,508	$ 69,801	$ 67,777	$ 64,910	$ 65,189	$ 64,008	$ 73,508	$ 64,910
Preferred Stock
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)	0	0	0	1,321,514	1,321,514	1,321,514	0	1,321,514
Stockholder's equity beginning balance	$ 0	$ 0	$ 0	$ 1	$ 1	$ 1	$ 0	$ 1
Preferred stock to common stock conversion (in shares)				(1,321,514)
Preferred stock to common stock conversion				$ (1)
Ending balance (in shares)	0	0	0	0	1,321,514	1,321,514	0	0
Stockholder's equity ending balance	$ 0	$ 0	$ 0	$ 0	$ 1	$ 1	$ 0	$ 0
Common Stock
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)	30,797,535	30,486,577	30,149,105	28,300,766	28,145,713	27,956,401	30,149,105	27,956,401
Stockholder's equity beginning balance	$ 32	$ 32	$ 32	$ 30	$ 30	$ 30	$ 32	$ 30
Exercise of stock options (in shares)	25,530	346,461	316,504	83,204	207,786	189,312
Exercise of stock options	$ 1			$ 1
Share-based compensation (in shares)		11,600	55,668	16,286
Deferred compensation issuance (in shares)		47,377
Stock dividends to Carilion Clinic (in shares)				770,454
Preferred stock to common stock conversion (in shares)				1,321,514
Preferred stock to common stock conversion				$ 1
Forfeitures of restricted stock (in shares)	14,700	(61,530)	(34,700)
Purchase of treasury stock (in shares)	14,700	32,950		333,953	52,733
Ending balance (in shares)	30,823,065	30,797,535	30,486,577	30,158,271	28,300,766	28,145,713	30,823,065	30,158,271
Stockholder's equity ending balance	$ 33	$ 32	$ 32	$ 32	$ 30	$ 30	$ 33	$ 32
Treasury Stock
Increase (Decrease) in Stockholders' Equity
Beginning balance (in shares)	1,672,741	1,639,791	1,639,791	1,305,838	1,253,105	1,253,105	1,639,791	1,253,105
Stockholder's equity beginning balance	$ (4,541)	$ (4,337)	$ (4,337)	$ (2,337)	$ (2,117)	$ (2,117)	$ (4,337)	$ (2,117)
Purchase of treasury stock (in shares)	14,700	32,950		333,953	52,733
Purchase of treasury stock	$ (125)	$ (204)		$ (2,000)	$ (220)
Ending balance (in shares)	1,687,441	1,672,741	1,639,791	1,639,791	1,305,838	1,253,105	1,687,441	1,639,791
Stockholder's equity ending balance	$ (4,666)	$ (4,541)	$ (4,337)	$ (4,337)	$ (2,337)	$ (2,117)	$ (4,666)	$ (4,337)
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity
Stockholder's equity beginning balance	90,305	89,446	88,022	87,006	86,356	85,745	88,022	85,745
Exercise of stock options	33	726	1,198	70	182	185
Share-based compensation	571	465	502	420	378	343
Deferred compensation issuance		78
Stock dividends to Carilion Clinic				113	90	83
Forfeitures of restricted stock	125	(410)	(276)
Stockholder's equity ending balance	91,034	90,305	89,446	87,609	87,006	86,356	91,034	87,609
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity
Stockholder's equity beginning balance	(15,995)	(17,364)	(16,248)	(19,511)	(20,262)	(21,305)	(16,248)	(21,305)
Stock dividends to Carilion Clinic				(113)	(90)	(83)
Net income	3,102	1,369	(1,116)	1,230	841	1,126
Stockholder's equity ending balance	$ (12,893)	$ (15,995)	$ (17,364)	$ (18,394)	$ (19,511)	$ (20,262)	$ (12,893)	$ (18,394)