Organization and Summary of Significant Accounting Policies - Revenue by Geographical Region (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 299.8	$ 381.4	$ 690.6	$ 557.1	$ 638.6	$ 851.1
Molecular diagnostic revenues
Disaggregation of Revenue [Line Items]
Total revenue	279.6	353.1	666.4	513.5	586.9	789.4
Molecular diagnostic - Hereditary Cancer
Disaggregation of Revenue [Line Items]
Total revenue	159.3		316.3		347.4	479.7
Molecular diagnostic - Tumor Profiling
Disaggregation of Revenue [Line Items]
Total revenue	33.9		120.9		48.3	43.0
Molecular diagnostic - Prenatal
Disaggregation of Revenue [Line Items]
Total revenue	37.6		106.8		76.7	104.9
Molecular diagnostic - Pharmacogenomics
Disaggregation of Revenue [Line Items]
Total revenue	29.8		93.7		74.1	112.6
Molecular diagnostic - Autoimmune
Disaggregation of Revenue [Line Items]
Total revenue	18.0		28.2		39.1	48.3
Molecular diagnostic - Other
Disaggregation of Revenue [Line Items]
Total revenue	1.0		0.5		1.3	0.9
Pharmaceutical and clinical services
Disaggregation of Revenue [Line Items]
Total revenue	20.2	$ 28.3	24.2	$ 43.6	51.7	61.7
United States
Disaggregation of Revenue [Line Items]
Total revenue	275.4		603.7		596.2	805.4
United States \| Molecular diagnostic revenues
Disaggregation of Revenue [Line Items]
Total revenue	255.3		579.5		559.8	767.6
United States \| Molecular diagnostic - Hereditary Cancer
Disaggregation of Revenue [Line Items]
Total revenue	140.9		271.0		329.8	466.7
United States \| Molecular diagnostic - Tumor Profiling
Disaggregation of Revenue [Line Items]
Total revenue	28.2		80.4		39.2	34.6
United States \| Molecular diagnostic - Prenatal
Disaggregation of Revenue [Line Items]
Total revenue	37.4		106.2		76.4	104.9
United States \| Molecular diagnostic - Pharmacogenomics
Disaggregation of Revenue [Line Items]
Total revenue	29.8		93.7		74.1	112.6
United States \| Molecular diagnostic - Autoimmune
Disaggregation of Revenue [Line Items]
Total revenue	18.0		28.2		39.1	48.3
United States \| Molecular diagnostic - Other
Disaggregation of Revenue [Line Items]
Total revenue	1.0		0.0		1.2	0.5
United States \| Pharmaceutical and clinical services
Disaggregation of Revenue [Line Items]
Total revenue	20.1		24.2		36.4	37.8
Rest of world
Disaggregation of Revenue [Line Items]
Total revenue	24.4		86.9		42.4	45.7
Rest of world \| Molecular diagnostic revenues
Disaggregation of Revenue [Line Items]
Total revenue	24.3		86.9		27.1	21.8
Rest of world \| Molecular diagnostic - Hereditary Cancer
Disaggregation of Revenue [Line Items]
Total revenue	18.4		45.3		17.6	13.0
Rest of world \| Molecular diagnostic - Tumor Profiling
Disaggregation of Revenue [Line Items]
Total revenue	5.7		40.5		9.1	8.4
Rest of world \| Molecular diagnostic - Prenatal
Disaggregation of Revenue [Line Items]
Total revenue	0.2		0.6		0.3	0.0
Rest of world \| Molecular diagnostic - Pharmacogenomics
Disaggregation of Revenue [Line Items]
Total revenue	0.0		0.0		0.0	0.0
Rest of world \| Molecular diagnostic - Autoimmune
Disaggregation of Revenue [Line Items]
Total revenue	0.0		0.0		0.0	0.0
Rest of world \| Molecular diagnostic - Other
Disaggregation of Revenue [Line Items]
Total revenue	0.0		0.5		0.1	0.4
Rest of world \| Pharmaceutical and clinical services
Disaggregation of Revenue [Line Items]
Total revenue	$ 0.1		$ 0.0		$ 15.3	$ 23.9