INVESTMENTS

The following tables summarizes investments by type of security as of December 31, 2017 and September 30, 2017, respectively (amounts shown in thousands):



December 31, 2017:	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Market Value
Available-for-sale securities:
U.S. Treasury, short-term	$	7,356	$	—	$	(16	)	$	7,340
Corporate debt securities, short-term	24,689		—		(30		)	24,659
U.S. Treasury, long-term	3,678		—		(13		)	3,665
Corporate debt securities, long-term	3,830		—		(13		)	3,817
Total	$	39,553	$	—	$	(72	)	$	39,481



September 30, 2017:	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Market Value
Available-for-sale securities:
U.S. Treasury, short-term	$	3,897	$	—	$	(3	)	$	3,894
Corporate debt securities, short-term	26,393		—		(8		)	26,385
Corporate debt securities, long-term	3,785		—		(5		)	3,780
Total	$	34,075	$	—	$	(16	)	$	34,059

The cost of securities sold is based on the specific identification method. Amortization of premiums, accretion of discounts, interest, dividend income and realized gains and losses are included in investment income.

The Company determines the appropriate designation of investments at the time of purchase and reevaluates such designation as of each balance sheet date. All of the Company’s investments are designated as available-for-sale debt securities. As of December 31, 2017 and September 30, 2017, the Company’s short-term investments have maturity dates of less than one year from the balance sheet date and the Company’s long-term investments have maturity dates of greater than one year from the balance sheet date.

Available-for-sale marketable securities are carried at fair value as determined by quoted market prices for identical or similar assets, with unrealized gains and losses, net of taxes, and reported as a separate component of stockholders’ equity. Management reviews the fair value of the portfolio at least monthly, and evaluates individual securities with fair value below amortized cost at the balance sheet date. For debt securities, in order to determine whether impairment is other-than-temporary, management must conclude whether the Company intends to sell the impaired security and whether it is more likely than not that the Company will be required to sell the security before recovering its amortized cost basis. If management intends to sell an impaired debt security or it is more likely than not that the Company will be required to sell the security prior to recovering its amortized cost basis, an other-than-temporary impairment is deemed to have occurred. The amount of an other-than-temporary impairment on debt securities related to a credit loss, or securities that management intends to sell before recovery, is recognized in earnings. The amount of an other-than-temporary impairment on debt securities related to other factors is recorded consistent with changes in the fair value of all other available-for-sale securities as a component of stockholders’ equity in other comprehensive income. No other-than-temporary impairment charges were recognized in the three months ended December 31, 2017 and 2016.

Fair Value Measurements and Disclosures

FASB ASC Topic 820, Fair Value Measurements (“ASC 820”) defines fair value, establishes a framework for measuring fair value under GAAP and enhances disclosures about fair value measurements. Fair value is defined under ASC 820 as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value under ASC 820 must maximize the use of observable inputs and minimize the use of unobservable inputs. ASC 820 describes a fair value hierarchy based on the following three levels of inputs that may be used to measure fair value, of which the first two are considered observable and the last, unobservable:


•	Level 1—Quoted prices in active markets for identical assets or liabilities;


•	Level 2—Inputs other than Level 1 inputs that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and


•	Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

The following tables represent the fair value hierarchy of the Company’s investments and acquisition-related contingent consideration as of December 31, 2017 and September 30, 2017, respectively (amounts shown in thousands):



	Balance		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
December 31, 2017:
Assets:
Short-term investments:
U.S. Treasury	$	7,340	$	7,340	$	—	$	—
Corporate debt securities
Financial	4,890		—		4,890		—
Industrial	9,918		—		9,918		—
Commercial paper
Financial	8,855		—		8,855		—
Industrial	996		—		996		—
Total short-term investments at fair value	31,999		7,340		24,659		—
Long-term investments:
U.S. Treasury	3,665		3,665		—		—
Corporate debt securities
Financial	1,902		—		1,902		—
Industrial	1,915		—		1,915		—
Total assets at fair value	$	39,481	$	11,005	$	28,476	$	—
Liabilities:
Acquisition-related contingent consideration	3,120		—		—		3,120
Total liabilities at fair value	$	3,120	$	—	$	—	$	3,120



	Balance		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
September 30, 2017:
Assets:
Short-term investments:
U.S. Treasury	$	3,894	$	3,894	$	—	$	—
Corporate debt securities
Financial	3,041		—		3,041		—
Industrial	9,503		—		9,503		—
Commercial paper
Financial	10,850		—		10,850		—
Industrial	2,991		—		2,991		—
Total short-term investments at fair value	30,279		3,894		26,385		—
Long-term investments:
Corporate debt securities
Financial	1,858		—		1,858		—
Industrial	1,922		—		1,922		—
Total assets at fair value	$	34,059	$	3,894	$	30,165	$	—
Liabilities:
Acquisition-related contingent consideration	354		—		—		354
Total liabilities at fair value	$	354	$	—	$	—	$	354

Acquisition-related contingent consideration is recorded in other non-current liabilities in the consolidated balance sheets. The following table includes a summary of the contingent consideration measured at fair value using significant unobservable inputs (Level 3) during the three months ended December 31, 2017 (amounts shown in thousands):



Balance at September 30, 2017	$	354
Issuance of contingent consideration	2,867
Expenses recorded due to changes in fair value	609
Issuance of common stock	(710		)
Balance at December 31, 2017	$	3,120