Liquidity and Capital Resources
Our cash, cash equivalents, and short-term investments consist primarily of money market funds and U.S. treasury bills. All of our short-term investments are classified as available-for-sale. The securities are stated at market value, with unrealized gains and losses reported as a component of accumulated other comprehensive income, within stockholders’ equity. As of December 31, 2019, our cash, cash equivalents, and short-term investments totaled $89.5 million, a decrease of $35.4 million from $124.9 million on December 31, 2018.
A summary of select cash flow information for the years ended December 31, 2019, 2018 and 2017 (in thousands):
2019 Compared to 2018
Cash provided by (used in) operating activities - Net cash used in operating activities was $34.1 million during 2019 compared to $69.9 million cash provided by operating activities during 2018, primarily due to a $74.4 million decrease in net income, a $25.6 million decrease in deferred revenue, a $4.2 million increase in other assets, a $2.1 million increase in accounts and other receivables and a $0.9 million decrease in accrued compensation partially offset by a $3.8 million increase in other long-term liabilities. The decrease in deferred revenue primarily reflects the effect of the adoption of ASC 606 on January 1, 2018. Cash used in operating activities was also affected by a $0.5 million decrease in non-cash charges primarily related to a $3.2 million decrease in stock-based compensation expense, partially offset by a $0.9 million impairment charge related to the SJ Facility right-of-use lease asset and a $1.3 million increase in depreciation and amortization expense. The increase in depreciation and amortization expense is due primarily to amortization of right-of-use lease assets and the shortened useful life of the SJ Facility leasehold improvements and a $0.3 million increase in deferred income taxes.
Cash provided by investing activities - Net cash provided by investing activities during 2019 was $10.9 million, a decrease of $2.7 million compared to $8.2 million cash provided by investing activities during 2018. Net cash provided by investing activities during 2019 consisted of maturities of short-term investments of $20.0 million. This was partially offset by purchases of short-term investments of $8.9 million and purchases of property, plant and equipment of $0.2 million. Net cash provided by investing activities during 2018 consisted of maturities of short-term investments of $26.0 million. This was partially offset by purchases of short-term investments of $17.7 million and purchases of property, plant, and equipment of $0.1 million.
Cash provided by financing activities — Net cash provided by financing activities during 2019 was $1.3 million, a decrease of $9.5 million compared to $8.2 million cash provided by financing activities during 2018. Net cash used in financing activities during 2019 consisted of $2.7 million used to purchase of treasury stock partially offset by $1.4 million in cash proceeds from stock option exercises and stock purchases under our employee stock purchase plan. Net cash provided by financing activities during 2018 consisted primarily of $8.2 million in proceeds from stock option exercises and stock purchases under our employee stock purchase plan.
2018 Compared to 2017
Cash provided by (used in) operating activities - Net cash provided by operating activities was $69.9 million during 2018 compared to $43.8 million cash used in operating activities during 2017. The $113.8 million change was primarily driven by $99.6 million increase in net income (loss), from $45.3 million net loss for 2017 to $54.3 million net income for 2018 and $27.0 million increase in deferred revenue, partially offset by $7.0 million increase in other assets, $4.2 million increase in prepaid expenses and other current assets, and $3.7 million decrease in accounts payable. The increases in deferred revenue and other non-current assets primarily reflected the effect of the adoption of ASC 606 on January 1, 2018. Cash provided by operating activities was also affected by an increase in non-cash charges of $2.6 million primarily related to higher stock-based compensation expense incurred for 2018 compared to 2017.
Cash provided by (used in) investing activities - Net cash provided by investing activities during 2018 was $8.2 million, a decrease of $2.8 million compared to $11.1 million cash provided by investing activities during 2017. Net cash provided by investing activities during 2018 consisted of maturities of short-term investments of $26.0 million partially offset by purchases of short-term investments of $17.7 million and purchases of property, plant and equipment of $0.1 million. Net cash provided by investing activities during 2017 consisted of maturities of short-term investments of $35.0 million partially offset by purchases of short-term investments of $23.8 million and purchases of property, plant, and equipment of $0.1 million.
Cash provided by (used in) financing activities - Net cash provided by financing activities during 2018 was $8.2 million an increase of $7.7 million compared to $0.5 million net cash provided by financing activities during 2017. Net cash provided by financing activities during 2018 consisted primarily of $8.2 million in proceeds from stock option exercises and stock purchases under our employee stock purchase plan. Net cash provided by financing activities during 2017 consisted primarily of $0.8 million proceeds from stock option exercises and stock purchases under our employee stock purchase plan partially offset by repurchases of treasury stock of $0.3 million.
We believe that our cash, cash equivalents, and short-term investments will be sufficient to meet our working capital needs for at least the next twelve months. Of our total cash, cash equivalents, and short-term investments of $89.5 million as of December 31, 2019, 5% was held by our foreign subsidiaries and subject to repatriation tax effects. Our intent is to permanently reinvest all of our earnings from foreign operations, and current plans do not anticipate that we will need funds generated from foreign operations to fund our domestic operations. We will continue to invest in, protect, and defend our extensive IP portfolio, which is expected to result in the continued use of cash. At December 31, 2019 there was $30.6 million remaining under our previously-approved share repurchase program. We anticipate that capital expenditures for property and equipment for the year ending December 31, 2020 will be less than $1.0 million. Cash from operations could also be affected by various risks and uncertainties, including, but not limited to the risks detailed in Part I, Item 1A, Risk Factors of this Annual Report on Form 10-K.
Table:
 |  | Years Ended December 31, | 
 | 2019 | 2018 | 2017
Net cash (used in) provided by operating activities | $(34,099) | $69,924 | $(43,829)
Net cash provided by investing activities | $10,920 | $8,237 | $11,068
Net cash (used in) provided by financing activities | $(1,331) | $8,205 | $518


Question: What affected the decrease in deferred revenue?
Answer: the effect of the adoption of ASC 606 on January 1, 2018.