Table:
|  |  | Year ended March 31, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
|  |  | (in thousands) |  |
| Net cash provided by operating activities | $66,235 | $46,412 | $32,514 |
| Net cash used in investing activities | (121,324) | (35,019) | (84,615) |
| Net cash provided by (used in) financing activities | 116,985 | 13,156 | (332) |
Paragraphs:
Liquidity and Capital Resources
Our principal sources of liquidity are cash and cash equivalents, investments and accounts receivable. The following table shows net cash provided by operating activities, net cash used in investing activities, and net cash provided by (used in) financing activities for the years ended March 31, 2019, 2018 and 2017:
In November 2015, we raised net proceeds of $68.3 million in our initial public offering after deducting underwriting discounts and commissions and offering expenses paid by us. In the years ended March 31, 2019, 2018 and 2017, we incurred operating losses of $1.2 million, $7.0 million and $10.4 million, respectively. While we expect to generate an operating loss in the year ending March 31, 2020, we expect to continue to generate positive cash flows from operating activities.
In the year ending March 31, 2020, we plan to continue to invest in the development and expansion of our Mime | OS™ platform to improve on our existing solutions in order to provide more capabilities to our customers. Investments in capital expenditures in the year ended March 31, 2019 were $28.8 million of which $25.8 million related to the expansion of our grid architecture.
We expect fiscal year 2020 capital expenditures to increase significantly as we expect to incur one-time costs related to the build out and expansion of facilities in the U.K. and other locations and additional data center expansion primarily in the U.S.
As of March 31, 2019 and 2018, we had cash, cash equivalents and investments of $173.5 million and $137.2 million, respectively. Based on our current operating plan, we believe that our current cash and cash equivalents, investments and operating cash flows will be sufficient to fund our operations for at least the next twelve months. Our future capital requirements may vary materially from those planned and will depend on certain factors, such as our growth and our operating results.
If we require additional capital resources to grow our business or to acquire complementary technologies and businesses in the future, we may seek to sell additional equity or raise funds through debt financing or other sources. We may also seek to invest in or acquire complement ary businesses, applications or technologies, any of which could also require us to seek additional equity or debt financing.
We cannot provide assurance that additional financing will be available at all or on terms favorable to us. We had no material commitments for capital expenditures as of March 31, 2019 or 2018.
Question:
What are the principal sources of liquidity?
Answer: cash and cash equivalents, investments and accounts receivable.