These factors include the ledipasvir/sofosbuvir single-tablet regimen not being approved by the PDUFA date of October 10, 2014. The level and speed of market acceptance of the STR, the pricing and rate of reimbursement for the STR, the amount of patient warehousing and wholesaler inventory decreases prior to approval of the STR which could negatively impact sales of Sovaldi. And finally the launch timing and market acceptance of competitive drugs already on the market or scheduled to enter the market later this year.
Turning to expense guidance, our non-GAAP product gross margin is expected to be in the range of 85% to 88%. We’re increasing our non-GAAP R&D expenses to be in the range of 2.3 billion to 2.4 billion as we continue to invest in our pipeline. We’re increasing our non-GAAP SG&A expenses to also be in the range of 2.3 billion to 2.4 billion, which assumes the continued build out and expansion of our commercial infrastructure in Europe and Asia to support HCV product launches and increased marketing and sales efforts related to the launch of our first oncology product.
For the full year, our non-GAAP effective tax rate is expected to be in the range of 17.5% to 20.5%. As Congress has not extended the federal R&D tax credit for 2014, we have excluded the credit from our guidance. If the R&D tax credit is extended in 2014, we would expect an additional 0.4% reduction in our annual effective tax rate.
We’re anticipating the full year diluted EPS impact of acquisition-related restructuring and stock-based compensation expenses to be in the range of $0.63 to $0.66 per share. This range includes the full year effect of the amortization of end process R&D related to Sovaldi.
Thank you and we look forward to updating you on our progress during our next call. We would now like to open the call for questions, operator?