Leases (Narrative) (Details)		12 Months Ended
	Feb. 19, 2019 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Jul. 01, 2019 USD ($)	Jun. 19, 2019 USD ($) ft²	Apr. 01, 2019 USD ($)	Feb. 25, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Aug. 31, 2015 USD ($)	Jul. 31, 2015 ft²
Lessee, Lease, Description [Line Items]
Net rentable area | ft²											59,248
Term of contract											96 months
Incentive from lessor										$ 1,400,000
Tenant improvement allowance									$ 8,200,000
Lease liability payments eliminated							$ 14,400,000
Operating lease payments due			$ 765,000
Remaining 2020			323,000
Base rent payments due 2021			442,000
Noncash leasehold improvements		$ 5,600,000
Noncash gain due to reduction of lease liability		1,300,000
Deferred cost of liability		900,000
Operating lease liability			693,000
Termination of lease cost		1,600,000
Other Noncurrent Liabilities
Lessee, Lease, Description [Line Items]
Deferred rent credit, noncurrent								$ 8,000,000
Nitto
Lessee, Lease, Description [Line Items]
Relocation assistance payment	$ 100,000
Security deposit difference payment	200,000
Rent reimbursement	$ 1,300,000
Lease net impact of modification (less than)		400,000
Initial direct cost liability						$ 3,800,000
ROU asset						2,900,000
Deferred credit, operating lease liabilities						$ 900,000
February Lease
Lessee, Lease, Description [Line Items]
Net rentable area | ft²							24,562
Term of contract							51 months
Operating lease payments due			4,800,000				$ 4,800,000
Remaining 2020			600,000
Base rent payments due 2021			1,200,000
Base rent payments due 2022			1,200,000
Base rent payments due 2023			1,200,000
Base rent payments due 2024			$ 600,000
New Premises
Lessee, Lease, Description [Line Items]
Net rentable area | ft²					8,727
Term of contract					2 years 6 months
Lease liability payments eliminated					$ 4,800,000
Base rent payments due 2021		400,000
Base rent payments due 2022		400,000
Noncash gain due to reduction of lease liability		500,000
Deferred cost of liability		200,000
Operating lease liability		$ 0
Initial direct cost liability				$ 800,000
ROU asset				600,000
Deferred credit, operating lease liabilities				$ 200,000