Common Stock	9 Months Ended
	Sep. 30, 2020
Stockholders' Equity Note [Abstract]
Common Stock	Common stockIn July 2019, we completed an underwritten public offering of 8,214,286 shares of our common stock at a public offering price of $70.00 per share. The offering resulted in net proceeds to us of $548.7 million, after deducting underwriting discounts, commissions, and other offering expenses. The primary use of the net proceeds was to fund our ADCETRIS and PADCEV commercialization efforts and our research and development efforts, as well as general corporate purposes, including working capital.