significant resources to product development activities. In particular, we are devoting substantial resources to the development of a new category of in-place associative computing products. Accordingly, we expect that our research and development expenses will continue to be substantial in future periods and may lead to operating losses in some periods. Such expenses as a percentage of net revenues may fluctuate from period to period.
Selling, General and Administrative Expenses. Selling, general and administrative expenses consist primarily of commissions paid to independent sales representatives, salaries, stock-based compensation and related expenses for personnel engaged in sales, marketing, administrative, finance and human resources activities, professional fees, costs associated with the promotion of our products and other corporate expenses. We expect that our sales and marketing expenses will increase in absolute dollars in future periods if we are able to grow and expand our sales force but that, to the extent our revenues increase in future periods, these expenses will generally decline as a percentage of net revenues. We also expect that, in support of any future growth that we are able to achieve, general and administrative expenses will generally increase in absolute dollars.
Acquisition
On November 23, 2015, we acquired all of the outstanding capital stock of privately held MikaMonu Group Ltd. (“MikaMonu”), a development-stage, Israel-based company that specialized in in-place associative computing for markets including big data, computer vision and cyber security. MikaMonu, located in Tel Aviv, held 12 United States patents and had a number of pending patent applications.
The acquisition was undertaken in order to gain access to the MikaMonu patents and the potential markets, and new customer base in those markets, that can be served by new products that we are developing using the in-place associative computing technology.
The acquisition has been accounted for as a purchase under authoritative guidance for business combinations. The purchase price of the acquisition was allocated to the intangible assets acquired, with the excess of the purchase price over the fair value of assets acquired recorded as goodwill. We perform a goodwill impairment test near the end of each fiscal year.
Under the terms of the acquisition agreement, we paid the former MikaMonu shareholders initial cash consideration of approximately $4.9 million. We are also required to pay the former MikaMonu shareholders future contingent consideration consisting of retention payments and “earnout” payments, as described below.
We also made cash retention payments totaling $2.5 million to the three former MikaMonu shareholders, conditioned on the continued employment of Dr. Avidan Akerib, MikaMonu’s co-founder and chief technologist. Retention payments of $743,000, $750,000 and $1.0 million were paid to the former MikaMonu shareholders during the quarters ended December 31, 2017, 2018 and 2019, respectively. We are not required to make any further retention payments.
We will also make “earnout” payments to the former MikaMonu shareholders in cash or shares of our common stock, at our discretion, during a period of up to ten years following the closing if certain product development milestones and revenue targets for products based on the MikaMonu technology are achieved. Earnout amounts of $750,000 were paid in the fiscal year ended March 31, 2019 based on the achievement of certain product development milestones. Earnout payments, up to a maximum of $30.0 million, equal to 5% of net revenues from the sale of qualifying products in excess of certain thresholds, will be made quarterly through December 31, 2025.
The portion of the retention payment made to Dr. Akerib (approximately $1.2 million) was recorded as compensation expense over the period that his services were provided to us. The portion of the retention payment made to the other former MikaMonu shareholders (approximately $1.3 million) plus the maximum amount of the