Equity Investment	9 Months Ended
Sep. 30, 2018
Inventory Disclosure [Abstract]
Equity Investment	Note 4: Equity Investment In September 2016, the Company purchased approximately 3.6 million shares of common stock of PACT Pharma, Inc. (PACT Pharma), a privately funded, early-stage biopharmaceutical company focused on adoptive cell therapy. The Company determined the fair value of such investment to be insignificant to the Company’s 2016 financial statements given the start-up nature of operations of PACT Pharma, and it was recorded at a nominal amount. In December 2016, the Company and PACT Pharma entered into a Master Services Agreement (the PACT Agreement) under which the Company provided PACT Pharma with general administrative support, including finance, human resources, legal, and other operational support. The Company also received certain warrants to purchase PACT Pharma common stock exercisable upon PACT Pharma’s achievement of certain valuation thresholds pursuant to the PACT Agreement. Also, in December 2016, the Company purchased 1.0 million shares of Series A preferred stock of PACT Pharma for $1.0 million. The Company determined PACT Pharma to be a variable interest entity, and that the Company has a variable interest in PACT. However, because the Company is not the primary beneficiary of PACT Pharma, it is not consolidating the results of operations of PACT Pharma in its condensed consolidated financial statements. The Company’s investment in PACT Pharma is accounted for as an equity method investment, and as a result the Company records its share of PACT Pharma’s operating results in interest and other income, net, in its condensed consolidated statement of operations and comprehensive loss. For the three and nine months ended September 30, 2018, the Company recorded $0.2 million and $0.6 million, respectively, and for the three and nine months ended September 30, 2017, the Company recorded $70,000 and $0.3 million, respectively relating to its share of PACT Pharma’s operating losses. As of September 30, 2018 and December 31, 2017, the Company had a $0.1 million and $25,000 receivable from PACT Pharma, respectively, for expenses the Company paid for on its behalf. In May 2018, PACT Pharma closed its Series B convertible preferred stock financing. The Company did not participate in this financing and therefore its equity ownership percentage in PACT Pharma decreased. As a result of the dilution in its equity ownership percentage and an increase in PACT Pharma’s estimated fair value per share, the Company recorded a gain of $1.2 million in interest and other income, net, during the nine months ended September 30, 2018 and an increase in the fair value of the investment balance in the condensed consolidated balance sheet as of September 30, 2018 by the same amount. The PACT Agreement also expired in accordance with its terms at the closing of PACT Pharma’s Series B convertible preferred stock financing. The Company monitors the investment for events or circumstances indicative of potential other-than-temporary impairment and makes appropriate reductions in carrying values if it is determined that an impairment charge is required. As of September 30, 2018 and 2017, no impairment charge was recorded. As of and for the nine months ended September 30, 2018 and for the year ended December 31, 2017, the Company also determined the fair value of the warrants to be insignificant to the condensed consolidated financial statements.

Note 4: Equity Investment

In September 2016, the Company purchased approximately 3.6 million shares of common stock of PACT Pharma, Inc. (PACT Pharma), a privately funded, early-stage biopharmaceutical company focused on adoptive cell therapy. The Company determined the fair value of such investment to be insignificant to the Company’s 2016 financial statements given the start-up nature of operations of PACT Pharma, and it was recorded at a nominal amount. In December 2016, the Company and PACT Pharma entered into a Master Services Agreement (the PACT Agreement) under which the Company provided PACT Pharma with general administrative support, including finance, human resources, legal, and other operational support. The Company also received certain warrants to purchase PACT Pharma common stock exercisable upon PACT Pharma’s achievement of certain valuation thresholds pursuant to the PACT Agreement. Also, in December 2016, the Company purchased 1.0 million shares of Series A preferred stock of PACT Pharma for $1.0 million. The Company determined PACT Pharma to be a variable interest entity, and that the Company has a variable interest in PACT. However, because the Company is not the primary beneficiary of PACT Pharma, it is not consolidating the results of operations of PACT Pharma in its condensed consolidated financial statements.

The Company’s investment in PACT Pharma is accounted for as an equity method investment, and as a result the Company records its share of PACT Pharma’s operating results in interest and other income, net, in its condensed consolidated statement of operations and comprehensive loss.

For the three and nine months ended September 30, 2018, the Company recorded $0.2 million and $0.6 million, respectively, and for the three and nine months ended September 30, 2017, the Company recorded $70,000 and $0.3 million, respectively relating to its share of PACT Pharma’s operating losses. As of September 30, 2018 and December 31, 2017, the Company had a $0.1 million and $25,000 receivable from PACT Pharma, respectively, for expenses the Company paid for on its behalf.

In May 2018, PACT Pharma closed its Series B convertible preferred stock financing. The Company did not participate in this financing and therefore its equity ownership percentage in PACT Pharma decreased. As a result of the dilution in its equity ownership percentage and an increase in PACT Pharma’s estimated fair value per share, the Company recorded a gain of $1.2 million in interest and other income, net, during the nine months ended September 30, 2018 and an increase in the fair value of the investment balance in the condensed consolidated balance sheet as of September 30, 2018 by the same amount. The PACT Agreement also expired in accordance with its terms at the closing of PACT Pharma’s Series B convertible preferred stock financing.

The Company monitors the investment for events or circumstances indicative of potential other-than-temporary impairment and makes appropriate reductions in carrying values if it is determined that an impairment charge is required. As of September 30, 2018 and 2017, no impairment charge was recorded. As of and for the nine months ended September 30, 2018 and for the year ended December 31, 2017, the Company also determined the fair value of the warrants to be insignificant to the condensed consolidated financial statements.