Summary of Significant Accounting Policies - Concentration of Risk and Limited Suppliers (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue Benchmark | Product Concentration Risk | DEFINITY
Concentration Risk [Line Items]
Concentration risk percentage	62.60%	53.30%	47.50%
Revenue Benchmark | Product Concentration Risk | TechneLite
Concentration Risk [Line Items]
Concentration risk percentage	24.90%	28.80%	31.60%
Accounts Receivable | Customer Concentration Risk | Company A
Concentration Risk [Line Items]
Concentration risk percentage		11.00%
Revenues | Customer Concentration Risk | Company A
Concentration Risk [Line Items]
Concentration risk percentage			12.00%
Revenues | Customer Concentration Risk | Company B
Concentration Risk [Line Items]
Concentration risk percentage			10.00%
Revenues | Customer Concentration Risk | Company C
Concentration Risk [Line Items]
Concentration risk percentage			10.00%