DNA (oligomers, or more particularly, oligonucleotides) to target specific genetic code sequences – that is, antisense therapy, a form of gene therapy. According to Riordan, he had always wanted to use the name Gilead Sciences all along, but used Oligogen as a temporary name because he needed to deal with a trademark clearance issue with a California nonprofit organization that was already using the word Gilead in its name. He had first heard of the Balm of Gilead when he read Lanford Wilson's play Balm in Gilead while in medical school, then learned that naturally occurring acetylsalicylic acid (aspirin) had been found in modern times in a willow tree species from that part of that world, and was therefore inspired to name his company Gilead. After founding Oligogen, he contacted the nonprofit about the naming issue and secured the right to use the Gilead Sciences name in exchange for a $1,000 donation. By 1988, the company had moved its headquarters to Foster City's Vintage Park neighborhood, where it has been based ever since. The company began to develop small molecule antiviral therapeutics in 1991, when the company in-licensed a group of nucleotide compounds including tenofovir. Riordan later recalled that Gilead's first decade as a startup was an extremely stressful experience for him, as a young venture capitalist serving for the first time as the founder, chairman, and chief executive officer of his own biotech company. The new company had no products and very little income, and narrowly escaped going out of business on several occasions: "It was touch and go for a long time". Finding a way for Gilead to make money was Riordan's top priority "every second of the day for eight years". 1990–1999: IPO Gilead's antisense intellectual property portfolio was sold to Ionis Pharmaceuticals. Gilead debuted on the NASDAQ in January 1992. Its initial public offering raised $86.25 million in proceeds. In June 1996, Gilead launched Vistide (cidofovir injection) for the treatment of cytomegalovirus (CMV) retinitis in patients with AIDS. In January 1997, Donald Rumsfeld was appointed chairman, but left the board in January 2001 when he was appointed United States Secretary of Defense during George W. Bush's first term as president. In March 1999, Gilead acquired NeXstar Pharmaceuticals of Boulder, Colorado. At the time, NeXstar's annual sales of $130 million was three times Gilead's sales; it sold AmBisome, an injectable fungal treatment, and DaunoXome, an oncology drug